Preparing your diesel engine for the upcoming season is a task not to be feared, as long as you follow a thorough checklist and take your time to ensure that each step is completed correctly. Here’s a guide to help you navigate the basics of the de-winterization process, and to ensure reliable performance and optimal engine health throughout the sailing season. 

1. Inspect the engine compartment. Start by looking for any signs of damage, leaks or corrosion that may have occurred during the winter months. Check all hoses, belts and connections for cracks, wear or deterioration, and replace any damaged components as needed.

2. Change the engine oil and filter. Drain the old engine oil and replace it with fresh, high-quality diesel-engine oil of the recommended grade. Also, replace the oil filter to ensure optimal engine performance and lubrication during the upcoming sailing season.

3. Check the fuel system. Look for signs of contamination or water buildup that may have occurred during storage. Drain any water or sediment from the fuel tank, and replace the fuel filters to ensure clean fuel flow to the engine.

4. Inspect the cooling system. Check the coolant level, and top off the coolant if necessary. Inspect hoses, clamps, and connections for leaks or damage. Ensure that the raw-water intake and cooling system are free from debris or blockages that could affect engine cooling.

5. Inspect and test the batteries. Check the condition of the batteries, and clean the terminals to ensure good electrical connections. Charge the batteries fully. Test them to ensure that they are holding a charge and are capable of starting the engine reliably.

6. Pre-lubricate the engine. Before starting the engine for the first time after winter storage, manually turn the crankshaft a few times using a wrench or socket. This helps circulate oil throughout the engine and prevents dry starts, reducing wear on engine components.

7. Start the engine and monitor it. Once everything is inspected, cleaned and prepared, start the engine, and let it run at idle for a few minutes to ensure proper oil circulation and fuel flow. Watch the engine gauges for abnormalities, and listen for unusual noises or vibrations that may indicate issues.

8. Do a test run. Take the boat out for a short ride to ensure that the engine is running smoothly and performing as expected. Monitor the engine temperature, oil pressure and other vital parameters, and address any issues immediately.

The post How To De-Winterize Your Diesel Engine appeared first on Cruising World.

Last month, I discussed “the big three” critical tasks every vessel owner needs to be able to perform: belt replacement, raw-water pump service, and fuel-filter service/fuel-system ­bleeding. This month, we’ll take a deep dive into fuel filters.

Internal combustion engines—and diesels in particular—rely on a handful of factors to run properly. They need compression, which is created by the pistons moving upward in the combustion chamber (in diesels, compression is what initiates combustion). 

These engines also need air to facilitate the combustion process. Finally, they need clean fuel because the fuel system has a high-pressure injection pump whose tolerances are often measured in ten-thousandths of an inch. Dirt and debris wreak havoc on pumps and injectors, which is why virtually all diesel-engine manufacturers specify the use of a primary fuel filter in addition to the on-engine secondary filter.

Servicing these filters, in most cases, is relatively easy. Along with changing the filters, the next-most-important goal is preventing air from being ingested into the fuel system.  

Most sail auxiliaries use pump-line-nozzle fuel-injection systems, which have been around since the advent of the diesel engine. It’s a system that is simple, robust, reliable, and requires no electricity, with the exception, in some cases, of a fuel solenoid. The system is not self-bleeding, which means if air makes its way into the fuel, the engine will stop. It won’t start until that air is manually removed, usually via fuel-system disassembly. If you have such a system, knowing how to purge air is mandatory. In this case, the proverbial ounce of prevention is worth the pound of cure: If you keep out the air when changing filters, bleeding won’t be necessary.  

When replacing the primary off-engine filter, if the fuel is heavily contaminated, you might need to wash or clean out the sediment or sight bowl, which in turn might require some disassembly. Depending on your primary filter model, this may be accomplished with no tools, or it might require removing some fasteners to drop the bowl. Either way, be prepared to get at and clean the parts that are exposed to fuel, other than the filter element, which you will replace. If “washing” is required, you can use clean diesel fuel or aerosol brake cleaner, a lint-free rag, and a soft bristle brush. 

Ideally, this task should be done outside or, if inside, in a well-ventilated area. If you have access to compressed air, that’s even better for blowing dirt off, or out of, parts. Be sure to wear safety glasses for this entire service.

For primary filters with drop-in elements, you may pre-fill the filter housing with clean fuel, from a separate container or by gravity from your tank, provided that the filter element is in place. This technique prevents any unfiltered fuel from bypassing the filter element. Fill the housing to the brim, avoiding as much air entrapment as possible. Otherwise, you can draw fuel into this filter using the engine’s lift-pump priming lever; that must be done with the filter fully assembled.

For secondary filters of the spin-on or sandwich variety, most engine manufacturers direct you to install the filter empty, then prime it once again using the lever on the engine’s lift pump. This is the safest approach because it reduces the possibility of dirt entering the outlet side of the filter, where it can then be transported by the fuel into the injection pump.  

Once both filters are fully reassembled and purged, start the engine and advance the throttle, in neutral, to a high idle of at least 1,200 rpm for two to three minutes. Doing so will allow the engine to pass small amounts of air without stalling. Then bring the rpm back to low idle and let it run for another 10 minutes to be certain that it won’t stall later—likely, just as you are backing out of a slip or ­weighing anchor on a windless day. 

Steve D’Antonio offers services for boat owners and buyers through Steve D’Antonio Marine Consulting.

The post How To Change a Fuel Filter appeared first on Cruising World.

Confession: I have an irrational fear. Not of heavy weather, but rather of having salt water back-siphon into my vessel’s diesel engine. Weird, right? 

Actually, not so weird. On new diesel installations, I’ve found that a common cause of premature engine failure is exhaust-related. 

Thus, a decade or so ago, when I installed a brand-new Perkins M92B in our 43-foot ketch, Ganesh, I paid careful attention to its exhaust system. I not only repeatedly rubbed it with hundred-dollar bills, but I also consulted various marine engineers and exhaust experts, including “Diesel” Dan Durbin, formerly of Parts and Power on Tortola, the guy who wrote the excellent “Please Don’t Drown Me” technical paper for Northern Lights. 

I’m totally anal about my exhaust system. For example: I have a custom drain on my marine muffler (Centek Vernalift) so that I can empty it during severe gales, or at least monitor the water level during extreme weather or after a 360-degree roll. Not only that, but the large exhaust hoses going into and out of that Centek muffler are different sizes at different points to reduce back pressure. And, yes, I’ve physically tested the back pressure in my system to make sure it is within spec. 

Even better, I have a water-exhaust separator (also Centek) mounted high up in my engine room, a setup that allows the raw water to flow out independently of my exhaust fumes. That’s right—my exhaust gases exit through one through-hull, and my exhaust water through another. 

Why so complicated? Because I am a poor man who sails in rough water with empty pockets, and I need my exhaust system to be bulletproof. It is much harder for a hose without salt water to allow salt water to back up into your engine than it is for a hose that contains salt water. 

Notice I said “much harder” but not impossible? That’s because nothing is really impossible for a determined, ­malevolent water molecule—nothing.

Anyway, the good news is that my system has worked perfectly, often in extreme weather conditions, for more than a decade and 50,000-plus ocean miles. The littlest details of seamanship matter most. For example, I always check my engine’s fluids before cranking up, and I always check the raw-water flow after cranking up. Always. (Well, except once in 62 years.) 

Here’s a quick overview of marine exhaust basics: There are two types. The hot-exhaust type is excellent at not allowing any salt water to back up into the engine, but the whole system is red-hot and often inadvertently catches the boat on fire; so often, in fact, that hot exhausts aren’t allowed on certain charter boats. They are just too dangerous on passenger-carrying craft. Fire at sea can be almost instantly life-endangering. 

It is much harder for a hose without salt water to allow salt water to back up into your engine than it is for a hose that contains salt water.

Most sailboats have a wet-exhaust system where the raw (salt) water mixes with the exhaust gases just after the ­manifold, and the coolish water/exhaust gets pumped into a muffler where the force of the exiting exhaust fumes lifts them both up and overboard. 

The problem with a wet exhaust is that there is always the possibility of water backing up and getting into the head of the engine. This often results in catastrophic failure of the engine—and, as a bonus, mental breakdowns among the boat’s owners. 

Which brings us to two days ago. I was waiting for a crowd of Singaporean friends to come aboard to go island-­hopping with us. They were slightly delayed. I checked the fluids in my engine, carefully eyeballed it, cranked it up (it started perfectly), and immediately visually checked its raw-water output by leaning over the side of my vessel. The raw water was pumping overboard just fine. Oh, what a good boy am I.

I ran my engine for a couple of ­minutes to allow it to come up to temperature, and then shut it off. During that time, I heard a clink, which I thought was something rolling off the cockpit table onto the cockpit sole. I lazily searched around the cockpit for the fallen object but couldn’t find it. (Clue.) No biggie, right? 

Once everyone was aboard, I recranked my now-warm engine, but this time it did not fire up on first revolution. It cranked a bit. That was unusual. (Clue: Anything unusual is a clue.)

Hmm, I mused to myself, thinking I needed to file, sand and clean my battery cables to get rid of any building corrosion. I did not check my raw water because, hey, I’d just checked it four minutes ago. What could go wrong in such a short span of time?

Plenty.

In blissful ignorance, I yelled, “Cast off!” at my wife, Carolyn, on our bow. She dropped the mooring pennant. 

All my Singaporean guests were ­huddled in the cockpit, thrilled to be underway on such a primitive, wild, daring-do sea adventure. 

“Is this safe?” asked a fellow who had never been on such a life-endangering voyage. 

“Oh,” I smirked confidently, “after three circumnavigations, I think I can get you to that placid isle called Ubin a few hundred meters ahead.”

Yes, pride always cometh before the fall. 

I attempted to increase my throttle—and, to my amazement, my engine slowed. It was at this point that it occurred to my seldom-used little pea brain that I might have a problem worthy of my feeble attention. (Clue: All problems are worthy of a skipper’s attention.)

While I was scratching my head where my hair used to be, and wondering if I had a throttle linkage problem, all hell broke loose. Huge billows of thick, gray smoke started coming out of all the hatches, companionways and opening ports. Coughing people came rushing on deck, terror in their eyes. 

“Fire!” someone screamed. 

All this happened quickly, just as I ­realized my engine was losing rpm because there was no oxygen in my engine room, only smoke. 

We were on fire. 

Carolyn and my daughter, Roma Orion, bravely hopped below to grab fire extinguishers, but both came shooting right back out, coughing heavily and bleary-eyed. 

“Poison!” Carolyn screamed. “Deadly gas!”

The situation was deteriorating quickly. Our Singaporean friends were desperately attempting to wave down a passing supertanker, screaming to be taken off Ganesh before their imminent and inevitable deaths at the hands of ocean-intoxicated, thrill-seeking Westerners.

My reputation as a respected circumnavigator was plummeting fast. I now did what I always do in emergencies: I glued on a confident smile, as if I possessed intelligence. I took a deep breath and asked myself, What the hell is going on? 

I shut off my engine and ordered the crew to the foredeck (they were all coughing and tearing up from the poisonous fumes). Next, I opened all the hatches for maximum ventilation, shut off the main battery switch (by feel while holding my breath) and, back on deck, unrolled the genoa to gain steerage. 

Once the engine and battery switch were off, the emergency was over. Well, except for our crying, terrorized guests, many of whom have since purchased rural property far inland. One claims to throw up whenever he sees a seascape. “It was exactly like the Titanic!” he tells his therapist and anyone else who will listen.

What, exactly, had happened? In a word: corrosion. When I initially cranked up, everything was fine until the clink. This sound was the flange connection between my manifold and exhaust system breaking three of its four corroded bolts. The breakage permitted the heavy pipe connection to gape open. 

Once there was no exhaust pressure in my exhaust system, there was nothing to force the raw water out of my muffler. Hence, my entire exhaust system and large-diameter hoses filled with seawater. 

After I shut off the engine the first time, some salt water flowed into my engine, not overboard. That’s why the engine hesitated while cranking the second time. But I didn’t realize the significance; I was too busy cracking dirty jokes in Mandarin. 

Mistake No. 2 was failing to recheck my raw water visually. It wasn’t pumping overboard, and if I’d have checked it, I’d have never cast off. Again, my bad. 

Before Carolyn cast off the mooring pennant, we were already in trouble. I was just too dumb to realize it. Pressurized salt water was spraying down the entire engine compartment. This caused numerous wires in my engine room to short out and begin melting their insulation. All this burning plastic, of course, produced massive toxic fumes. 

Once we were back on the mooring, we aired out the boat, unloaded all the praying, happy-to-be-alive, we’ll-never-go-to-sea-again guests, and attempted to troubleshoot our problem. 

Troubleshooting, of course, requires intelligence—why I thought I should be involved, I have no idea. I put Carolyn to port and Roma Orion to starboard, and cranked up the engine. They were supposed to tell me if they saw any new smoke or any tiny drips of water. 

Roma was immediately drenched with salt water. From where? The raw-water ­injection riser after the manifold, where the raw water gets injected into the exhaust system to cool it. 

At this point—idiot of limited ­intelligence that I am—I figured that I fully understood what had just happened. The hose clamp or hose had failed where the raw water goes into the injection point, and it had squirted under pressure, setting off a chain reaction. 

Clever, me not. 

At 3 a.m. the following day, I sat up in my bunk and said, “Oh, darn!” At first light, I unwrapped the vision-blocking fireproofing from the exhaust flanges that connect the manifold to the exhaust system. That’s when I saw the large, angled gap between the two. Without exhaust pressure in the system to evacuate the raw water, my engine exhaust system had filled completely with salt water. When I shut off the engine for the second time—thinking the emergency was over—the natural rocking and pitching of the vessel allowed salt water to get back-splashed into my cylinder head.

I now did what I always do in emergencies: I glued on a confident smile and asked myself, What the hell is going on?

The evil, ever-focused water molecules had finally had their day. I’d been too ­myopic to think through all the ramifications of the squirting water. Thus, corrosive salt water had been trapped in the cylinders for 18 long hours before I managed to get it out, and to fire up my no-longer-so-new engine. 

How much damage did this salt water do? I don’t know. My engine currently starts fine. And runs OK. (Yes, I changed the oil a couple of times.) But, surely, having the engine flooded with salt water for almost a day didn’t help its compression, now or tomorrow. 

And do I have another $20,000 laying around for a new engine? Nope! I could barely afford the new exhaust gasket and my extra-large serving of crow.

Why write such a depressing sea yarn? Because, as the T-shirts say, “Poop happens.” Despite a lifetime of guarding against salt water getting into any of the numerous engines that I’ve installed, my ever-plotting nemesis finally won a round. 

 Cap’n Fatty and Carolyn are currently in Langkawi, Malaysia, slapping paint on their bottom. (Did that come out right?)

The post Exhausted In Singapore, For All the Wrong Reasons appeared first on Cruising World.

Diesel engines, because they generate a considerable amount of soot, are hard on oil. If you aren’t accustomed to seeing how quickly oil turns black after being changed, you might be surprised by it. 

Soot thickens oil, which makes it more difficult for oil to flow into tight tolerances, especially when cold. Also ­hastening lubricating oil’s ­demise: anything that slips past the piston rings and enters the crankcase. This includes the byproducts of diesel combustion (such as nitrogen oxide, carbon monoxide and particulate matter), fuel (which dilutes and thins oil, lowering its viscosity), and combustion gases and moisture (which lead to the formation of acid). 

New oil is fortified with additives that stave off this deterioration—to a point. The single most important driver of oil changes is acid formation, which is offset by a base additive that neutralizes the acid. Oil analysis calculates this acid-neutralizing ability as the total base number, or TBN. Most new oil starts out with a TBN of 8 to 10; as acid production is offset, that numbers falls. When it reaches 2.5, it’s time for an oil change.

Technically, oil changes should be driven by this figure, however, unless you are prepared to carry out oil analysis (something I strongly recommend), you have no idea of your oil’s condition. You instead must replace it based on engine hours or the calendar. Some oil requires changing every 150 hours or six months, while other oil allows for as much as 450 hours or annual replacement. 

The oil you use must meet or exceed the ­specification in your engine owner’s manual. Oil designed to be used in diesel engines has an American Petroleum Institute-designated C prefix, as opposed to oil destined for use with gasoline engines, which has an S prefix. The C prefix is followed by a second letter that signifies the type of additive package. 

You must also use the weight of oil that your engine manufacturer specifies. This might include, for example, a 15W-40 or a straight 30 weight. Stay consistent, and avoid mixing letters or weights. 

Oil filters are every bit as important as the oil itself. Quality and construction run the gamut, so don’t skimp; you usually can’t go wrong using the engine ­manufacturer’s brand, but these can cost ­considerably more than common retail brands available at auto-parts stores. Having cut open many oil filters over the years, I am impressed by and have had good results with WIX and NAPA Gold filters.

Make certain the area around the filter is clean before and after removing the old filter, and remove the old gasket with the filter. An old gasket will not make a proper seal with a new filter; it can squirt out the entire contents of the crankcase in less than a minute.

Many sail auxiliary engines have a drain hose attached to the bottom of the oil pan, where an oil pump can be connected. (I prefer the manual-vacuum variety. Engine oil should be warm but need not be at full operating temperature to pump easily.) When you’re finished, make sure the drain hose cap is reinstalled. You’ll need two wrenches: one to hold the hex base nut and the other to turn the cap nut. 

Refill the engine to the full mark on the dipstick, run the engine for 30 seconds or so, shut down, wait a minute for the oil to run fully into the crankcase, check the dipstick again, and add oil if necessary to top off.

Steve D’Antonio offers services for boat owners and buyers through Steve D’Antonio Marine Consulting.

The post Diesel Engine Oil Change and Oil Filters Paramount to the Life of the Engine appeared first on Cruising World.

Last month I reviewed some of the reasons an engine or genset might not start. This month I’ll delve into reasons an engine might crank but not actually start.

When an inboard diesel cranks, several things happen. Air is drawn into the cylinder or combustion chamber via the air-intake manifold/filter, passing through intake valves as the piston is drawn down the cylinder, creating a vacuum. As the piston returns, the intake valve closes, pressurizing the air. On a common gas engine, the compression ratio is roughly 10-to-1, and the compressed air is mixed with fuel vapor. On a diesel engine, the compression ratio is much higher, roughly 20-to-1, and the fuel is not mixed with the air until after compression has occurred.

While a higher compression increases the thermal efficiency of an engine, in the case of a diesel, it’s mandatory. As the air is compressed, its temperature increases, and in the case of a diesel, it’s hot enough to ignite the fuel when it’s injected into the combustion chamber by the injection pump and injector. If a diesel’s compression is insufficient, the air will not be hot enough to ignite the fuel. For this reason, a conventional diesel smokes on startup; the combustion chamber is still relatively cold, inhibiting complete combustion, and that white smoke is minute droplets of unburned fuel. So, low compression can be a reason for difficult starting (or not at all). This can be caused by worn piston rings, sticking or improperly adjusted valves, or a starter that turns too slowly (between 150 and 250 rpm are required for a diesel engine to start). Malfunctioning glow plugs—either the plugs themselves or the solenoid that controls them—can also make for hard or no starting.

Another aspect of this is the injection of the fuel. For conventional pump-line-nozzle (i.e. non-electronic) injection systems, fuel passes from the tank to a primary coarser (usually 10 to 30 microns) filter, usually via rubber hose, often to a water separator with a clear bowl. From there it’s on to a low-pressure (or lift) pump, after which it flows into a steel line, where it then enters the finer (in the 2- to 7-micron range) secondary fuel filter. It’s then on to the high-pressure injection pump, and finally to the injectors, again via steel lines. In this sequence, the most common causes for failure are clogged filters, a defective lift pump or air in the lines.

Your primary fuel filter should be equipped with a vacuum gauge; without one you are essentially flying blind, with no way of knowing how hard your lift pump is working to draw fuel through that filter. So if you don’t have a vacuum gauge here, I strongly recommend you install one; it’s a valuable troubleshooting tool, and it will alert you when that filter should be replaced. If, while cranking, you observe the vacuum gauge climbing, there is a restriction somewhere between the lift pump and the filter; naturally, the element itself should be checked and changed if there is any doubt.

Read More: Monthly Maintenance

If the vacuum remains low, below roughly 3 inches of mercury, then move on. The vacuum gauge will not alert you to restrictions that happen after the lift pump, including the secondary filter. However, if you change that filter when you change the primary filter, it’s unlikely to be the culprit. Regarding filters, it’s worth noting that some lift pumps include their own integral filter or screen, which can become obstructed.

Air can make its way into a high-pressure fuel system several ways, but most often at primary filter housings, in tanks low on fuel, and in plumbing unions between the tank and lift pump. Air will be drawn in only where a vacuum is present, between the tank and the lift pump, so concentrate on inspecting those areas: At rest, they might leak some fuel. Make sure everything is tight. Then try bleeding the high-pressure system to purge any air that might be present.

Finally, on older engines, it is possible for the injection pump and injectors to wear out, and/or become fouled with carbon, respectively. If the engine has more than 3,000 or 4,000 hours on it, pump wear reaches a point where fuel pressure is low enough to prevent combustion. This is often preceded by easy cold starts, where fuel viscosity is higher, and hard hot starts, where fuel viscosity is lower. Also, if the injection pump uses an electric solenoid-type stop plunger, these can fail or become stuck. Some engines energize the plunger to run; others energize it to stop. That’s an easy fix and well worth checking.

Steve D’Antonio offers services for boat owners and buyers through Steve D’Antonio Marine Consulting (stevedmarineconsulting.com).

The post Troubleshooting a Sailboat’s Auxiliary Diesel Engine appeared first on Cruising World.

Recently, a member of a forum in which I participate shared a plea for help with an engine that would not start: “When I try to turn it over, I get nothing.” Should you need similar assistance, get the terminology right. If you turn the key to the crank position, wherein the starter usually engages and the engine rotates, and you get no response, the engine “will not crank.” If you turn the key and the starter engages, it “cranks but will not start.” Most key switches have three positions: off, run and crank. The latter is spring-loaded, so it stays engaged only while you are turning it; when you let go, the key returns to the run position.

If it does not crank (i.e., it doesn’t even click when the key is turned to the start position), it’s a clear electrical problem. The culprit is usually the starter itself or the battery; the wiring leading to the starter (from the battery or key switch) also might be compromised. First, check and cycle the battery switch; these can fail and contacts can become oxidized if not used for long periods.

Next, turn the key switch to the run position: Do the instruments respond? If not, electrical power to the engine is somehow compromised; check all of the connections at the starter, both large and small, for any that might be loose or corroded, or where ring terminals are not properly crimped. And don’t forget to check the large DC negative cable where it is connected to the engine block, or in some cases to the starter directly.

Most engines have a button-type circuit breaker on the engine that protects the power supply to the instruments and key switch, including the starting circuit; if it trips, the instruments will not respond when the key is turned to run, and the engine will not crank. These breakers can be notoriously difficult to find on the engine because they are small (a little larger than an eraser) and sometimes painted the same color as the engine. Find out where yours is located. This circuit also might be protected by a fuse—again these can be hard to locate because they are rarely labeled.

If you have no power to the instruments and you can use a multimeter, check for voltage at the start battery; it should show roughly 12.4 to 12.6 volts at rest, with no load and no charger. If the charger is on, you should see something over 13.4 volts. If you do have power, move on to the starter’s large post, to which the large red cable is connected. You should see roughly the same voltage there; if there is no voltage, that’s the problem: A battery connection is compromised, or the battery switch is off or defective.

If you do have power at the large post, the next test is the starter solenoid. Many engines use a yellow wire with a red stripe for the cranking circuit; it should indicate 12 volts when cranking only. If the key is turned to the crank position and you observe no power at this post, the key switch or its wiring is the issue.

While conducting these tests, it’s important to not only have a good ground for the multimeter, but it also should be the same ground the engine is using. Don’t connect the meter’s black lead directly to the battery; connect it where the large, black negative cable is attached to the engine block. Before taking any readings, confirm that this is a good ground by touching the red lead directly to the battery positive post or a known positive source. Doing so will ensure all of your subsequent meter readings are valid. There might be other causes, but the above are among the most common.

Glow plugs, if the engine is equipped with them, are usually actuated with a separate spring-loaded switch; however, some keys also might have a glow-plug position. In some cases, the engine will not crank unless the glow plugs are actuated (reminding you to use them); however, if this switch is compromised, it can prevent the engine from cranking, so it should be part of the troubleshooting process. Assuming the engine uses a pump-line-nozzle injection system (i.e., non-electronic) and it cranks but will not start, that’s almost certainly fuel-related. But it could be several other things, which I’ll discuss next month.

Steve D’Antonio offers services for boat owners and buyers through Steve D’Antonio Marine Consulting (stevedmarineconsulting.com).

The post Monthly Maintenance: What To Do When the Engine Won’t Start appeared first on Cruising World.

Antifreeze is a critical component in any liquid-cooled internal combustion engine that relies on a closed cooling system. It should be referred to as “coolant” because it does much more than prevent freezing.

In a closed cooling system, excess heat created by the engine is absorbed by the coolant and transferred, via a heat exchanger, to seawater and pumped overboard with the exhaust gases. From the 1930s through the 1990s, nearly all coolant used in applications like this was the familiar green ethylene glycol (referred to as IAT, or inorganic acid technology), which provided corrosion protection and circulator-pump lubrication, offered freeze prevention down to about minus 30 degrees Fahrenheit when mixed at a 50-50 ratio with water, and elevated the boiling point about 15 degrees Fahrenheit above that of ordinary water. Pressurized cooling systems, such as those on all modern diesel engines, also raise the boiling point; at 15 psi, the boiling point of ordinary water is 250 degrees Fahrenheit.

Today things are different, mostly in the realm of choice; there is a range of coolants from which to choose, ­including organic acid ­technology (OAT), hybrid ­organic acid technology (HOAT) and ­nitrided organic acid technology (NOAT), along with some proprietary coolants designed for specific engines. These formulations afford engines greater corrosion protection and longer coolant life. Then there’s color: In addition to green, there is blue, pink, orange and red, and while those colors might be indicative of a particular chemistry, it’s no guarantee.

Always follow the coolant instructions provided by your engine’s manufacturer, and never add coolant without knowing what’s there already. In an emergency, you are better off adding water (preferably distilled, but anything will do in a crisis) than the incorrect coolant. The primary mission of coolant is to prevent freezing, but if that’s not an issue, water will work just fine short-term.

When changing ­coolant, whether to a similar or different chemistry, plan on flushing the system to remove sediment and all traces of old coolant. Remember, conventional ethylene glycol is poisonous, so don’t leave uncovered containers out where they can be accessed by pets or children, and always clean up spills (it evaporates very slowly), and dispose of old coolant properly.

If you’ve decided to replace your coolant, you should once again do so in accordance with engine-manufacturer guidelines, and in the absence of those, about every 1,000 hours or three years. Unless the manufacturer specifies one of the above-mentioned more-modern varieties, most sail auxiliaries and gensets can use conventional IAT; however, it should be formulated for diesel-engine use.

Diesel engines, particularly those that rely on a “wet” cylinder—wherein the outside wall of each engine-cylinder liner is in direct contact with the coolant—can experience a phenomenon known as cavitation erosion, sometimes called ringing. At each power stroke, the cylinder bulges slightly and then rapidly contracts, creating a void or cavitation bubble that implodes violently, and in doing so, removes some metal from the liner. This all occurs on a microscopic basis and takes time for damage to occur, but after enough time passes, it can lead to cylinder-­liner leakage and failure. This is rare on sailboat auxiliaries, but why risk it? By using a high-quality diesel-rated coolant (these include anti-cavitation additives), and changing it regularly, you will all but eliminate this possibility. Supplemental anti-cavitation additives are also available, and these can be added on an annual or hours-based model.

If you are using a concentrate (that is, a coolant that requires the addition of water as opposed to one preformulated), be sure to mix with distilled water only. Do not use tap or bottled water. Water that contains minerals can leave scale deposits within the cooling system, thereby impeding heat transfer. Unless otherwise instructed by the manufacturer, the mix ratio should be 50-50 for the best balance of corrosion, freeze and boil protection, as well as heat transfer (pure distilled water can transfer more heat than coolant, which is why it’s undesirable to increase the coolant-to-water ratio beyond 50 percent). Anything under a 30 percent ratio of coolant can allow biological growth to form within the cooling system, especially on engines that are used infrequently. So stick with the 50-50 ratio for the best results.

RELATED: Sailboat Diesel Engine Analysis

Finally, if you’ve never checked the coolant concentration in your engine, you should do so, especially before winter layup. If the coolant concentration is too low, it will freeze, which could cause significant and possibly irreparable damage to the engine. While the “floating balls” test tool works for ethylene glycol, a refractometer is more accurate, and it’s applicable to all coolant types.

Steve D’Antonio offers services for boat owners and buyers through Steve D’Antonio Marine Consulting.

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“Come back tonight,” said Jamie’s new friend, a businessman in a remote Indonesian port. He had agreed to help us buy diesel. It’s technically illegal to purchase in Indonesia as a non-citizen, and yet we all find a way…eventually. After several dead ends, this fellow was our ticket. We had been repeatedly foiled: in a part of the country where foreigners are presumed to be one of the three Ms (missionaries, miners, or mercenaries), our uncertain status meant interrogation and secret police trails. We had a very real challenge to source fuel; the offers of new friends inexplicably rescinded, fading into the inscrutable highlands. Of course this man preferred that we shuttle the goods from our clandestine transaction under cover of darkness!

For cruisers who venture just a little way off the beaten path, and even for some those who don’t, finding the fuel we all consume (despite the lovely white flappy things) and getting it into your tanks can sometimes be a little complicated.

Fuel docks may be sprinkled around where boating is popular in North America. Yet in many parts of the popularly cruised world, the fuel dock is a rare commodity. Along Totem’s westabout circumnavigation we used fuel docks in Mexico, again in Australia, in Malaysia, then South Africa, and then not again until we landed back on the US East Coast. A little more than one per ocean: that’s not much, and we are hardly sailing purists! Oh, there was probably a dock in Tahiti that we didn’t use, but I do remember dinghy wrangling against a rough concrete wharf in Nuku Hiva while dropping 50-liter (13+ gallon) jerry cans over the scrabbly edge as we rose and fell with the foaming surge. No fuel dock for us in Nuku Hiva, or any of the Marquesas island group.

What do we do? It varies by location, and jerry cans feature prominently. The name “jerrycan” references the German origins, and the slang name for Germans when these were designed in the 1930s. Those were pressed steel; plastic rules now, sometimes covered for UV protection.

Totem’s back end is wide for a classic plastic, leaving ample room behind our center cockpit for lashing cans (currently, five) to stern rails. Amidships with a board to distribute weight and support is common.

A bushel of peaches; Enough rice to feed our family for about four months; An average four-year-old child—these are things that weigh as much as a jerrycan full of diesel! There’s storing them… and then there’s schlepping them.

Given weight combined with awkward size, it’s worth thinking about how to get these around. In our early cruising days, we had a robust hand truck that served the purpose. In later years, we relied more on muscle.

Sometimes accommodation can be found (a stray grocery cart). In the Sea of Cortez this last year, the crew of Avalon shared their trailer (combined with bike or scooter) to lighten the load of fellow cruisers.

Particularly innovative: flat-pack carriers from Dacoblu. The brainchild of a Swedish cruiser we met in Saint Helena (as you do, moorings adjacent), these are durable, wearable backpacks – specially designed for carrying fuel (or water, just don’t mix them up) comfortably on foot. It even doubles as a dinghy tank! They can roll up and stow easily when empty. We tested and are impressed.

Sometimes it’s not a jerrycan that gets us fueled. In Maldives, the fuel barge is scheduled to come to your location in the anchorage near the capital city of Male. With an umbilical fuel hose connecting barge to boat and vessels throwing wakes as they fly by, the operation is tricky.

In Papua New Guinea we fueled from barrels are brought alongside; crews spun up a manual crank to feed diesel up to the waiting boat.

The fueling experience we’ll never forget: in Brunei, with our Qatari guide. None of us were legally supposed to purchase (subsidized) fuel in the country. A story of persistence, perseverance, begging, refusal to admit defeat, and a whole lot of jerry cans…buy us a beer sometime, we’ll kick back and tell the tale!

We love sailing; one of the reasons I’m so excited about our big passage to French Polynesia next month (NEXT. MONTH!) is the promise of days under sail: glorious! But carrying fuel is unavoidable, and there is a paucity of fuel docks to make it easy once you strike out.

Our goal is to take off from Mexico in the first week of April. Lists have spawned lists in an effort to stay organized. After nearly four years in North America, we’re feeling the looming gap from the land of Easy and Access, and trying to keep focus.

Last weekend was our final bit of travel before departure – it was a lot of fun to share an evening with the Bluewater Cruising Association and an honor to headline their Ocean Adventurers Series for 2020. The chance to visit my parents, and aunties, a very dear cousin and her adorable baby were sweet… and now that it’s behind us, there’s no pushing off passage prep!

For many cruisers, this is where you look over the edge of what feels like a very steep cliff. We’re not immune to that gut-dropping feeling of a major passage, but the dynamics are a lot different than when we did it from this same spot ten years ago. The stressors come from different places, this time. Not the unknown of weeks at sea, but the farewells, the miles we’ll put between ourselves and family, the tenuousness of supporting ourselves through the internet – and heading into the land of minimal connectivity.

Coaching services hiatus

We’ll stop taking new coaching clients at the middle of this month. One of the tenets of our business is the personal connection we make with everyone who reaches out for our support to help them go cruising. With time skewing towards our own prep and limited internet access ahead, it simply makes sense. We can serve existing clients on lower bandwidth, but really like the opportunity to better connect through video chats for new relationships; that won’t be possible for a while. When we start up again is as certain as a cruiser’s route plan – “written in sand, at low tide!” – but likely from Samoa or Fiji, around August or September. If you’re keen to be on our call list when we do, just send us a quick note.

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It started with a question. “Are you in this class?” the man on my right asked. “Yes,” I replied. “Marine diesel, right?” We were all awaiting the start of the diesel-engine class. And there I was, with a pink scarf draped around my neck, hair pulled back in a ponytail, and a bright blue purse slung over my shoulder. It was then that it hit me:* I’m the only woman here*.

But why would that stop me? My husband had taken the class a year before, and I wanted to know just as much as he did about our Yanmar 4JH3E. I wasn’t about to let a room full of testosterone prevent me from that. I wanted to become a better asset to our two-person sailing team. We had aspirations of traveling the world together aboard our Baba 40 sailboat, The Pioneer. I hoped that by taking this class I would be able to diagnose potential engine problems and provide ideas in solving them.

I’d scanned the room for an open seat just like a new kid in a middle school lunchroom. I could feel a lump in my throat. Just find a seat. I inhaled a shallow breath and saw a vacant spot between two men in the front row. I nervously excused myself as I wiggled my way down the row toward the empty seat. My classmates stared at me with eyes that said, What are you doing here?

“Hi, I’m Hannah” I smiled as I held out my hand. “Hello,” the bearded man replied, with a gruff shake. The three of us started up a brief conversation. I discovered one owned a trawler in New England, and the other planned to charter a sailboat in the Caribbean for vacation. When the instructor arrived, as he scrolled through his roster, he showed no sign of surprise that a girl was taking his class. A seasoned diesel mechanic and teacher, he proceeded to lead us through a series of PowerPoint slides, explaining the necessary balance among air, heat and fuel needed to propel a diesel.

As we covered the basics of fuel injectors, the hydraulic process, and the properties of diesel, my pen flew across the pages in my notebook in a mad dash to capture as much of the content as I could. I sketched little pictures to go along with my notes. Every now and then, the man next to me peeked over his glasses at what I was writing. Did he think my notes were girly? My insecurity swelled.

When the instructor discussed how the use of glow plugs heats an engine before ignition, I started wondering why we did not have glow plugs on ours. So, without much more thought, I jerked my hand into the air: “How does the engine get warm enough to start if there aren’t any glow plugs?”

Once the words had left my mouth, I could feel my cheeks burn a flushed crimson, and I realized all eyes were now upon me. Oh, no. Was that a stupid question? Did everyone already know this? Were they all annoyed I had asked?

Over the course of the class’s first hour, not one student had dared to ask a question. Since I’d been the first, I wondered if I was even supposed to ask questions at all. My heart was throbbing. To my relief, the instructor appeared unfazed by my question. He explained that larger diesel engines, such as our 54 hp Yanmar, did not need glow plugs because they relied on compression to heat them to a high enough temperature for fuel ignition on their own, with just the hot high-pressure air.

I went back to my note taking and hoped that if I had another question, other students would speak up and ask questions too so I wouldn’t look like an idiot. But no one did. The instructor even asked a few times at the end of a section if the class had questions; instead, the men looked around, out the window, or down at their complimentary copy of Nigel Calder’s Marine Diesel Engines: Maintenance, Troubleshooting, and Repair. And then we learned about the possible causes of different-colored engine smoke: black, white and even blue. I found myself wondering why burning oil made blue smoke, so I shot my hand up again.

After taking my question, I caught the instructor looking around the classroom. Several students looked up interested, and a few nodded their heads. Perhaps they had had the same question about blue smoke too? I felt less ashamed this time. Were they relieved that I was raising my hand with their questions so they wouldn’t have to?

A man from behind me leaned forward and whispered: “Thanks. I actually had been wondering that too.”Oddly enough, the instructor appeared pleased that I had asked, and used it as a segue into the next segment on oil maintenance and changing oil filters. He walked us through a series of diagrams on how worn valves or aged guide seals in the cylinder head weaken, and oil seeps into them over time, causing the oil to burn. And the chemicals in oil often burn a bluish color. Made sense.

As I looked around the room, it dawned on me that the men wanted to appear manly to their fellow men. From the time they’d been boys in the high school locker room, their male ego was on the line. This class was no different. Masculine ego was dictating that they pretend to understand everything about superchargers, turbochargers and mixing elbows so the other men in the class would respect them too. Asking questions showed weakness. And they were desperate to look knowledgeable about manly things like engines. In reality, they’d learn a lot more if they’d let down their guard about what all the other men in the class thought of them and started asking their questions too.

But was that too much to ask? What would it take for just one of them to take the risk of asking a question and potentially open the floodgates for the other men in the class to ask their questions too?

And then it finally happened. We were covering the material about hydrostatic locks and what to do if an engine made a clunk, clunk, clunk sound instead of turning over to start. The man from behind me shot his hand up into the air. You could have heard a pin drop. I knew how he must have felt as all eyes were now on him. But I did not dare turn around. I did not want to add to his embarrassment, and I was cheering inside.

I don’t remember his exact question, but I do know the instructor’s answer was to check the raw-water pump first. He had a broad grin on his face, and his eyes seemed to be telling the rest of the men in the class that asking questions was the brave, manly thing to do.

It didn’t take long for another hand to go up asking about how often to change the coolant in the closed cooling system. Answer: every one to two years. Less than a half-hour later, a third man asked about his Westerbeke engine and whether he should be checking his zincs more frequently. The answer was yes, at least monthly.

By the end of the day, my questions had been joined by a chorus of at least five others. And the next day, the class model evolved into even more questions and discussion as more and more men felt comfortable enough to voice what they did not understand.

Whether my asking questions made a difference at the start of the day, I will never know. But as I sat there surrounded by the “diesel-engine shop talk,” I recognized something else that I took away from the class as invaluable.

I might not equate my self-worth with how much I know about raw-water pumps, hydraulic transmissions and heat exchangers, but I do recognize that the way to gain more confidence is by investing in yourself by asking questions, taking classes, and learning from others who are more knowledgeable than you. I might be uncomfortable or feel out of place at first, but that discomfort will propel me toward the more confident, knowledgeable person I hope to be, regardless of gender and societal stigmas.

It will make me a better sailor too, which is the reason I was there in the first place. That “extra” lesson was a bonus.

Hannah Knecht spent several years sailing and cruising aboard The Pioneer, a Baba 40. She is now the program director for Hands Across the Sea, a nonprofit organization founded and run by cruising sailors that promotes literacy in the Eastern Caribbean.

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Working as a marine engineer I get called to inspect a lot of boats and have to make quick determinations of whether the engine is ready for sea or, in the case of a pending sale, to check the condition of the motor before purchase. To do this, I have devised what I call a fast Engine Technical Analysis to help find problems before they become a sea story.

In essence, an ETA is an advanced system of inspecting a boat’s drive train. I perform these tests to help catch pending mechanical issues before leaving the dock. An analysis is much more comprehensive than a typical pre-departure peek at the engine. I visually inspect the motor, of course, but also take a series of measurements that become a base line for future tests. The goal is to use this analysis to help make easily informed decisions about the boat’s drive system now and in the future.

The steps to performing an engine analysis include a visual inspection, a more detailed evaluation of fluids and equipment, a load test, and analyzing the numbers. Here’s how to perform one:

Visual Inspection

To get started, give the engine a general once-over, looking for blatant flaws and obvious irregularities. Open the engine room door (or compartment) and look, feel and smell.

Look for oil drips or other fluid under the engine. Inspect for obvious cracked hoses. Give a gentle bend where a hose attaches to the engine and look for cracks in the rubber cover or for loose hose clamps. Check the fan belts for cracks. Grab the alternator pulley and see if it will spin free on the belt. If it does, the belt is worn or loose.

Feel the inside of the engine room for any oil film. Touch the areas of the engine you can’t see, feeling for rust or salt trails.

Smell for any burned chemical type odor. Smells can be difficult to locate, but in general any burnt, oily or diesel aromas should be searched out. A good nose can tell the difference between a hot belt and a hot wire.

Look over the complete engine for oil leaks. Pay particular attention to the front seal and the area between the gearbox and engine. Leaks in the front or rear seal can mean a coming engine rebuild. Inspect the head-to-block seam, looking for oil or water trails.

Take photos from all angles as a base line for later use.

This is the point where many an engine inspection ends, but in an analysis, we want better scrutiny to help build confidence in the propulsion system.

Details, Details

The next series of checks focus on fluid inspections. With the engine off and cold, check the following:

Oil: Oil is the lifeblood of any engine. It lubricates, cools and quiets the diesel. But how do you know if the oil is doing its job? Begin by pulling the dipstick. Smell for signs of diesel odor. Diesel could mean a leaking fuel pump or an injection pump about to go bad. Pinch a small dab of oil between your index finger and thumb, and expand slowly to see how far you can spread the oil before the gap opens. Take a photo and compare this gap to new oil. Write down the difference in your notes. This is a crude method of checking viscosity and diesel intrusion.

Open the oil fill and look inside the cap for water droplets, condensation or worse, a gray gooey substance indicating water penetration into the oil. Put a small drop of oil on a paper towel and compare it to a new oil drop. Note the amount of black carbon and any shiny deposits.

A more careful inspection can include a look inside the oil filter. Next time you change the oil keep the old filter. Leave it to drain upside down, then cut open the canister and look at the inside of the element. It’s the inside of the paper filter that will contain any heavy deposits or metal shavings. Take photos for later comparison.

Later, when you start the engine, note the oil pressure. Do so again during the load test, and a third time immediately upon reducing throttle after the test. Does the gauge needle dip? It should remain steady from start up and through all the following tests. A dipping gauge can indicate a faulty oil pressure release valve or worn engine bearings.

Coolant: A typical yacht engine has two cooling-water loops: fresh water and raw water. Let’s look at the freshwater loop first. With the engine shut off and cool, open the expansion-tank cover or the heat-exchanger cover — or where you check the coolant water. The reservoir should be filled almost to the top with green or red coolant. A low coolant level can mean a small air leak in a hose.

Check the coolant for oil. It should look new and fresh. The underside of the cap should be clean. No brown, gooey oil or rust should be present under the cap. Any strange colors can mean a failing heat exchanger or failing head gasket.

Next, find the saltwater pump. Inspect for leaks, green drips and rust streaks. Pay particular attention to the area between the pump and the engine. Any leaks mean the internal seals are failing; or maybe a clogged heat exchanger or exhaust elbow is causing back-pressure on the pump.

Diesel Filter: Locate your diesel filters. Most boats have two sets, one on the engine supplied by the manufacturer and a pre-filter or set of filters, often marked with the Racor brand. On the bottom of most fuel filters, there will be a drain valve. Drain off a small amount of fuel into a container and check it for water, dirt and any long, stringy algae. If you find more than a couple teaspoons of water or much dirt, then it’s probably time to change the filters. If your filter system has a vacuum gauge, note the readings in the log for future comparison.

Once you’re done with the engine’s fluids, move on to other critical elements.

Control system: The engine control system, which includes the shift and throttle levers at the helm, directs a skipper’s intentions to the motor. Inspecting the components is critical. For example, if the engine fails to engage in reverse during docking, the results can cause boat damage or worse. Begin by feeling for play in the shifting linkage. Move the controls through all possible motions, feeling for hard spots. Does neutral have a detent or click to signal the transmission is in neutral?

Inspect where the cables attach inside the shifting housing. Look at each split pin for wear. Wiggle and physically inspect each connection looking for cracks, breaks or anything that looks amiss. Pay particular attention to where the cable cover end attaches to the shift housing. If this point slips, you can lose engine control immediately.

Inspect the cable at the engine, and look for chafe from engine vibration. An area where the plastic cable cover has chafed through can let in small amounts of water that will corrode the cable in areas where it can’t be seen, causing an unpredictable loss of engine control.

Gearbox and coupling: Inspect the gearbox-to-prop-shaft flange bolts. Attempt to tighten the Allen setscrews in the coupling. Loose bolts or setscrews indicate a vibration or misalignment. Pull the gear-oil dipstick. Check the level and perform the viscosity check again. Look for water under the cap and smell for any burned odor. Most yacht gearboxes don’t have a filter so any bits of crud or metal keep getting recirculated. It is imperative to keep an eye on the oil.

Starter load test: Place the jaw of a clamp-amp electrical meter over the positive cable leading to the starter. Clip your voltmeter to the starter’s positive and negative. Hold the stop button or manual engine shutdown while turning the engine over for 10 seconds. (The engine should not start.) Note the starter amp draw. On a typical 40- to 75-hp engine the starter draw reading should be 225 to 275 amps. Look at the starter for a rated amperage or wattage (watts/volts=predicted amps). They should match what you see on your meter. Drawing more amperage could indicate poor cables, a bad armature in the starter or failing batteries. The voltage during this test should remain above 9.5 volts at the starter. The results of this test should be placed in your notebook and the vessel’s log for future reference. This is an important test as it indicates if the starter is about to fail, and helps troubleshoot later problems.

Air inlet: In order for a diesel to run efficiently, it needs a large amount of good, clean, cool air. Here are some tests to help ensure the quality of the air feed to the engine: With the engine off, pull the air filter and inspect for cleanliness. Reach a finger down the air inlet. It should be lightly covered in dirty, but not gritty, oil. Any loose oil or splatter indicates a possible faulty intake valve, or maybe a turbo failing. Check for grit, indicating a leaking air filter. If the engine has a turbo charger, you might be able to reach inside and give the blades a spin. They should move easily with no restrictions or any bumps.

Load It Up

The next series of tests duplicate the engine working under load, such as when motoring hard into a head sea. If the engine is relatively small, the idea is to pull against the dock lines while safely tied in the marina. This test can also be performed at anchor, if the boat is run hard in reverse. Larger yachts with more horsepower will need to conduct these tests while underway. Note: It is imperative to inspect the dock lines, anchors and cleats for suitability for such loads. Double up your spring lines and inspect the dock cleats before beginning. Be sure to locate the manual shutdown on the injection pump, and be ready to shut the engine off if you suspect any problems.

Start up check: Start the engine; wait a couple seconds for oil pressure to build. First off, before the batteries have had time to charge, test to see if the alternator is operating at full output. With the engine in neutral, increase the throttle to 1,000 rpm. Set your clamp amp to DC and place the jaws around the positive/red cable at the back of the alternator. Check the output and note the DC reading. Change the meter to AC and again note the reading. The AC reading should be around 3 amps. If the AC reading is near half of the DC reading, this indicates a faulty alternator diode. Return at the end of your testing and verify the voltage has stabilized around 14.2 volts.

Seawater flow test: While the engine continues to warm up, increase the throttle to about 2,000 rpm in neutral. Take a bucket to the engine exhaust and time how long it takes to fill the bucket with exhaust water. This number will come in handy if you ever suspect a failing impeller, clogged raw-water loop or clogged exhaust riser.

RELATED: Quieting Your Boat’s Engine

Load tests: Wait for the engine to warm up (maybe 5-10 minutes). Put the engine in forward (reverse if this is a test at anchor). Slowly bring the engine up to half throttle. Check all the dock lines one more time. If all the lines and cleats appear strong then slowly increase the engine to full throttle.

From wide open, reduce the engine speed by 200 rpm for testing. For example, a Yanmar might have a max rpm of 3,600, but would only reach 3,400 pulling against the dock lines, and thus should be run at 3,200 rpm for the remaining tests. In other words, run the engine hard, but not overloaded. A motor in good condition, properly installed, should be able to run under this type of load for hours without overheating or causing other problems.

Before proceeding, recheck the dock lines and cleats.

Look at the engine mounts. They will be taking the thrust of the engine and should be compressed forward. Inspect them for any indication they are “rolling out,” indicating a coming failure. Even under strain, the rubber-mounted studs should still sit vertically. Look for metal-to-metal contact in the base. At the end of the load test, run the engine hard in reverse and recheck the mounts. Take photos of the mounts under load for later comparison.

Check for smoke: As the engine comes up to full temperature, you might see signs of smoke. Determine if it is escaping from the engine, or simply gassing-off an old film of oil and dirt. Pay particular attention for smoke escaping from between the engine and exhaust manifold. This may be combustion gas that could contain carbon monoxide, which is a dangerous, colorless, odorless gas that can kill when released into confined spaces.

Inspect the back of the engine. Take a good look at the shaft-to-gearbox coupling. It should be sitting almost perfectly smooth. Any pumping, fore-and-aft motion could indicate failing engine mounts. A circular motion could indicate a bent shaft, out-of-alignment engine or possibly a damaged prop.

Look at the packing gland for the amount of water dripping past the shaft into the boat. Compare this to the manufacturer’s recommendation. Be sure to note the amount of drips over a 60-second period and write this in your notebook and the ship’s log, as it’s a common point of worry for crew. Remember, when motoring at speed there will normally be less dripping at the packing gland due to the forward motion of the boat causing a low pressure or suction at aft end of the hull. (This is why some skiffs will self-drain when they get up to speed.)

Temperature tests: By now the complete engine should have stabilized in temperature. It’s time to do a few tests with an infrared thermometer. If you have not used a laser temperature gauge before, you’ll be amazed at how much information this simple tool will show you about an engine. They can be purchased from most tool shops for about $30.

Begin by scanning the ­gearbox looking for hot spots. Pay careful attention to the gearbox output bearing and the area of the case around the clutch packs. If any part of the gearbox is going to build up heat, it will be during this pull test. The complete gearbox temperature should be under 170 degrees F; 120 degrees F is typical.

Continue checking with the laser gauge along the cylinder head. It should read about 180 to 190 degrees F everywhere. There should be no hot spots. A hot spot would be more than a 10-degree change in the head from one end to the other.

Note: Testing the area ­directly around the exhaust ­manifold does not count as a hot spot, as this will be hot due to the high temperature of the exhaust. Concentrate on the area around the injectors.

Check the oil temperature by shooting the oil filter and oil pan. The oil temp should be about 7 to 15 degrees above the head temperature, but not above 220 degrees F.

Check the inlet ­temperature to the saltwater pump and the outlet of the final heat ­exchanger. The difference should be less than 15 degrees. A higher difference can indicate an engine producing too much heat (perhaps because of a failing head gasket) or too little water flow (a clogged saltwater system).

Next, check the freshwater temperature inlet and outlet of the heat exchanger. The difference should be about 15 to 20 degrees F and stable. You should be able to move the thermometer beam along the body of the heat exchanger and show the cooling effect of the heat exchanger. By this method you can see how much reserve cooling you have left in the heat exchanger.

If your engine is turbocharged, the pre-turbo exhaust temperature should be about 550 to 750 degrees F.; the after-turbo should be between 150 and 250 degrees F lower. Check the exhaust gas temp between the cylinders and exhaust manifold for each cylinder. Normal for a loaded non-turbo engine is ­between 450 and 550 degrees F. A ­cylinder temp lower than the rest shows a clogged injector or perhaps a dead cylinder. A high cylinder temp possibly shows a leaking exhaust valve or poor injector spray pattern.

Turbo pressure test: If the engine has a turbo, then before the load exam, find a test port on the intake manifold and install a pressure gauge to check the turbo boost. Compare this to the manual. Many turbochargers boost up pressure to 30 psi. Most Yanmar engines boost to around 18 psi. The pressure should be stable. Any cycling of pressure, or coughing, can indicate after burning, blow-by or a clogged air inlet.

Reduce throttle tests: Take one last look for any signs of problems and slow the ­engine down to an idle. With the ­infrared thermometer, check to see if the engine cools quickly, in less than five minutes.

Verify the alternator is ­producing 14.2 volts. Less means the voltage regulator needs to be inspected, and more may mean the batteries could fail early.

Shut the engine down and be sure to take careful notes on ­every reading you took.

For most yacht owners, an in-depth inspection of the ­vessel’s drive system can mean more confidence, safer travel and a much easier time of finding trouble spots in the ­future. Remember to keep careful records and photos of all the tests performed so down the road when something has changed, you can repeat the tests, make short work of the ­troubleshooting and get back to enjoying time on the water.

Scott Fratcher is a licensed marine engineer who has acquired over 300,000 sea miles. He was a critical member of Earthrace that currently holds the Union International Motonautique Round The World speedboat record. Scott now lives in New Zealand with his wife, Allison.

Gear Up

• Here is the equipment needed to perform a thorough engine analysis:
• Camera
• Notepad
• Clamp amp meter; ­electrical multi meter
• A 0- to 45-psi pressure gauge (if your engine has a turbo)
• An infrared thermometer
• Any other special tools the engine might require
• A few rags and spray cleaner

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