With spring almost upon us, I would like to share some information from an engine and generator service done on our boat when she reached five years old. Jeff Leitch of Bay Shore Marine in Annapolis spent time with me while conducting a thorough service of the single Deere diesel engine and Westerbeke generator. I think his observations apply to any trawler or cruising motorboat with diesel engines and a generator. For older boats, especially, this info can be particularly helpful, especially if you are planning a major trip this year, such as Alaska, the Great Loop, or New England. Whether the boat is new or just new to you, I’m sure you prefer trouble-free cruising.

If you own a trawler that is considerably older than the five-year-old trawler I’m talking about here, I think it makes great sense to schedule a survey of the engine room. An experienced engine surveyor will not only be familiar with your engines, but all the supporting systems that keep them operational. He might suggest, for example, that it is well past time to replace those exhaust hoses in that 1979 Grand Banks 42, which get brittle after decades of use. Are they original? No matter, time to change them.

The list of other recommended projects might also include modernizing/upgrading some of the electrical wiring on the boat, for two reasons. Wiring best practices have changed significantly since the boat was built, and who knows how many people added electrical equipment without regard to how best to install them. You’ll find evidence of that on almost any used vessel, power and sailboats.

(Below: A video from 'Ryan & Sophie Sailing on routine diesel engine maintenance.)

When it comes to routine annual maintenance, many trawler owners choose to do the work themselves. Kudos to these owners, who develop a close relationship with the inner workings of their boat, which is a big confidence factor when out cruising. While not everyone is mechanically inclined, I think turning a wrench once in awhile brings a certain satisfaction.

Others take advantage of their favorite yard or engine service company for whatever maintenance is necessary and to prevent a problem from developing. This is important to keep everything running and shipshape. We all love a boat that doesn’t miss a beat when we are on the water.


(See: Cap Sante Marine & Northwest Marine Center Merge To Become Seattle Yachts Service)


Over the years, I have had numerous people ask at seminars what they should do in their engine room, what they should check, and what kind of maintenance is important, and how often. I recommend finding a good engine service company in your area that is familiar with your engine. Then schedule an appointment where they will perform the maintenance, but with you present to learn and watch. In my experience, the right engine techs will gladly explain what they are doing, what they are looking for, and why certain things are important. The service life of certain components is well known to them, and such information may not be readily found in a manual. You will even see what tools they use for certain tasks and learn some of their tricks to get things done.

After spreading blankets, tools, filters, oil, hoses, and other parts in the cockpit and saloon, Jeff first inspected the main engine cooling system, while his assistant went over the boat’s Westerbeke 5kW generator. Jeff talked about what he was doing while he worked, and I took lots of notes.

Jeff checked to see if the coolant solution in the main engine was good down to 20 degrees below zero, more than enough for this part of the country, where subfreezing temperatures are rare. He told me that we should consider flushing the complete cooling system, which he recommends every five years. We’d spent the previous winter down in the Florida Keys, so the system was due for a good flushing.

He then checked the tightness of the four engine mounts for the Deere 6081 diesel engine. Two of the mounts needed to be tightened.

I was surprised to see that the transmission oil cooler zincs were completely gone, their bolt heads located out of sight under some hoses. The yard techs had obviously missed them in previous services. (This is a big reason why I prefer engine guys over yard workers.) Jeff replaced both zincs with new ones.

Jeff came aboard in the fall, but he likes to schedule the rest of the work in the spring, at the start of the season. Jeff checked for leaks around the valve cover gasket as well as around the turbo and planned to check the valves and their adjustment in the spring. He went on to explain that the belts, valves, and impellers are best done in the spring, although they could really be done anytime.

But it is his way of doing things, starting off a new season with newly serviced parts.

(Seen below: Boaters University is offering a marine diesel maintenance online course.)

boaters university course

I learned the importance of the five-year milestone, with respect to seals, hoses, gaskets, and fittings. Enough time passes that some components need replacing as part of overall preventative maintenance. He insists that replacing the hoses on the engine is worth considering if we planned a big trip this coming season. It would be unfortunate to have a problem with five-year-old hoses giving out during a trip far from home. And while a some of the hoses are standard enough to be easily sourced from a local boatyard, other hoses are preformed and need to be ordered from a Deere dealer. So, if your boat has not had these parts replaced and your boat is 10 years old or older, it might be prudent to address these hoses before you take off for the season.

Over on the generator, Nick found that sacrificial zinc material in the Westerbeke’s cooling system had broken down and bits from the anode clogged some of the tubes in the heat exchanger. To fix this means the heat exchanger must be removed from its housing and thoroughly cleaned out and inspected. He also decided that job would be done in the spring.

Jeff and Nick then changed the fuel filters for the main engine, the dual Racor Model 75/900 filter elements, the Racor Model 500 fuel filter for the generator, as well as the on-engine fuel filter on the Westerbeke. Then we fired up the engine and generator to warm the oil in preparation for oil changes in both engines and the Twin Disc transmission. The boat has a Reverso oil changing system to remove oil from both engine and generator, but Jeff pointed out he would never use the Reverso pump to put oil back into an engine unless the oil changing system was carefully backflushed.

When Jeff replaced the engine oil filter, he ran his fingers along the oil filter fitting to make sure there was no grit or dirt on the mating surfaces. Then he put John Deere Plus-50 oil into the six-cylinder 6081 engine, which effectively extends the oil change interval by 50 percent to 375 hours.

Later he added a bottle of FPPF Marine Formula Fuel Treatment into the boat’s two fuel tanks, adding that I should regularly inspect the gaskets on the fuel fill fittings on deck, as they age and eventually break down, and few people think to check them. Cracked gaskets will let water seep into the fuel tanks even when the boat sits at the dock. Mine were fine, but I noted the value of checking these gaskets regularly at the fuel dock.

With fuel systems taken care of, and oil changes completed, Jeff removed the air filter and cleaned out the inside of the filter housing. The filter looked clean, but the inside of the housing was filthy with an oily residue, which was soon cleaned up with a rag.

Our Zimmerman 36 came equipped with a Tides Marine dripless shaft seal, and Nick removed the hose and capped it for the winter. Our boat will sit in the water at our dock, and it is one less thing to go wrong. It will be reattached in the spring.

As Jeff cleaned up after the oil changes, he mentioned that Windex works great on the chromed parts of Growler’s engine to remove oil smudges and grease. (I’d had several engine parts chromed after seeing the Deere display engines at the Ft. Lauderdale show several years before.)

The rest of the boat had already been winterized, so when they left the boat, I put an oil-filled heater in the engine space, with its heat setting just under medium. I felt it was extra insurance should the winter be colder than normal, but it proved unnecessary.


Completing The Job

Spring came in April, and Jeff Leitch returned with another assistant, Chris, and the rest of the service was completed. Chris tackled the generator’s clogged heat exchanger, while Jeff took off the valve cover as he prepared to check the valve adjustment on the main engine. The special flywheel adjustment tool that John Deere incorporated into the engine design is a great feature most engine manufacturers don’t provide. Jeff used it to slowly turn the flywheel on the big engine to achieve top dead center so he could check the valve clearance and adjust each valve as necessary.

Without the tool he would have to endlessly bump the starter or try to turn the flywheel without reduction…not an easy task on a large engine. (Example below.)

flywheel tool

The tool turns the engine over using just a ratchet, but it takes time to run through a full rotation of the flywheel. Once he reached top dead center (TDC) for one cylinder on the engine, he inserted a pin through the engine block into a hole in the flywheel that marks that specific point in the flywheel rotation. This locks the intake and exhaust valves into position where they can be checked and adjusted as necessary.

It turned out that every valve needed some adjustment (all intake valves were loose), and Jeff ran through the cycle twice to make sure he got all valves to their proper clearances. He dabbed a drop of oil on each adjustment screw to show it had been checked and adjusted.

Satisfied that the valves were done, Jeff cleaned the valve cover and then put a bead of quick-fix adhesive on the cork gasket on the valve cover. That will keep the gasket mated to the cover when it is removed in the future, rather than have it tear if it sticks to the engine block. Then he put a light coating of grease on the gasket before he set it down on the top of the engine and replaced the eight bolts holding down the chromed valve cover.

While Jeff was busy with the valves, Chris drained the coolant from the Westerbeke generator so he could remove the heat exchanger. Once he pulled the bundle of tubes out of the housing, we could clearly see the severity of the gunk in the heat exchanger. It was not pretty. Hoping to clean the heat exchanger at our dock rather than a trip back to the shop, he used a special product that works amazingly well. He poured Barnacle Buster into the exchanger in a three-to-one concentration, which cleaned out the clogged exchanger tubes. The solution bubbled away the nasty material and left the exchanger tubes clean. Chris was able to clean the heat exchanger using chemicals on our dock rather than with equipment in his shop. Barnacle Buster is worth checking out if you have similar issues.

Chris put the heat exchanger back together and started the generator. He put his hand on the raw water pump, explaining that if it remained cold that meant the pump was working. If it was not working properly, it would get warm very quickly.

With just a couple of things left to do, Jeff moved to the front of the main engine, as he prepared to remove and replace the raw water impeller. Settling into a comfortable position in the cramped space, he commented that on a big-block diesel, it is probably excessive to replace the impeller every year. Maybe every other year is good.

When he got the impeller out of the gear-driven raw water pump, he noted that the beefy rubber impeller was starting to wear down the cam in the pump, evidenced by small ridges on the surface of the cam, easily felt with one’s hand. We installed a Speed Seal cover a couple of years earlier to make this job easier, and Jeff noted how the impeller had scored the stainless-steel cover ever so slightly. We will probably replace the cam in the pump next year.

We then started the engine to flush out the anti-freeze, to check the heat exchanger in the big Deere. When the end cap was removed, Jeff saw very minor scaling on the bottom of the heat exchanger—no problems there.

Jeff also looked closely at the serpentine belt at the front of the engine. No dust or cracks could be found on the belt, and it looked in fine shape.

They then ran the main engine and generator under load. We removed the hatches over the engine and generator and moved them into the cockpit, so we could look, smell, hear, and feel how everything was going. After about 10 minutes, they felt comfortable the job was done. Good to go for another cruising season, but we made notes to change the raw water pump cam, engine hoses, and flush out the cooling system next spring.

I found it is very worthwhile to follow the procedures of these experienced guys performing their work, and I trust this is helpful to you as well. I don’t think I’ll ever be able to do everything they did as I’m not as gymnastic as I used to be in tight spaces, but it is good to have the knowledge of what needs to be done and how. Knowing that you need to check something is one thing, but it is much better to know precisely what you are looking for, and what to do about it. On some trawlers reaching engine mounts, for example, is an easy proposition, while on other boats it can be quite difficult.

I’ve learned a lot with every boat I’ve owned and know that I can depend on the engine and generator if we’ve done our best to ensure there are no surprises and that everything is as it should be.

I hope you have also developed the same confidence in your boat and its systems. That is the best way to make sure this coming season’s cruising is memorable and perhaps the best ever.


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