How to get the most out of a yacht engine
Last updated: 31/01/2019
Overhauling a marine engine can be a costly and time consuming job. Taking that extra step to properly maintain your superyacht engine can lead to thousands of extra hours of work before an overhaul is required.
The average marine gasoline engine runs for 1,500 hours before needing a major overhaul; however, in the same conditions, the average marine diesel engine will run for more than three times that long, with an average of 5,000 hours.
Diesel engines are built to finer tolerances than gasoline engines. They will accept much more abuse and can even deliver, if well maintained, 8,000 hours of hard work before a major overhaul is needed. Since the average recreational boater logs about 200 hours per year, meaning an 8,000 hour diesel engine would last 40 years; theoretically, a well-maintained diesel can last for the lifetime of your yacht.
Pierre Obweon, managing director at Palmawatch S.L. commented, “The adverse conditions under which marine engines operate have a great deal to do with their longevity. Naval architects recommend that engine compartments should be supplied with lots of dry, cool and clean air.”
Protecting your engine through storage
Storage is important for helping to maintain the life span of an engine; see below for some important points that can help. To make sure engines perform well, ensure these six important steps are completed to properly store your diesel systems.
All sealed up
Jeff Heotzler, marketing director at ATL Fuel Bladders stated, “Unless properly treated, diesel — especially the newer bio-diesel and low-sulphur fuels — can grow stale and prone to bacterial and fungal infestations while in storage (known as diesel bug)”. This results in sludge and sediment that can plug filters, create starting problems and damage engines.
An empty fuel tank invites condensation, and over time this results in water collecting in the bottom of the tank, posing a serious problem for diesel engines. To help prevent any of these issues, fill up before long-term storage. Then treat the fresh fuel with a diesel biocide. After treating the fuel, install new primary and secondary fuel filters, and then bleed the fuel lines to eliminate any air pockets.
Used diesel engine oil contains acids and other contaminants that can eat away at metals over time. So ditch the old oil now. To change the oil, run the engine for a few minutes to warm up, then shut down and drain/pump out the old oil, change the filter and fill the crankcase with fresh oil.
Open all drain plugs to purge the water-cooling systems. Use a stiff wire to clear any sediment from drains. Also, bump the ignition to turn over each engine, without starting it, to clear water from the pumps. If your boat stays afloat all year round, you can drain the systems by first closing the seacocks for the raw-water inlets, then removing the inlet hoses and intake-pump covers, as well as all drain plugs. After clearing the raw-water systems, replace all of the drain plugs.
To avoid freeze damage and fight corrosion over winter, plumb the motor flushers or intake pumps with rust-inhibiting, antifreeze and run each engine until the solution exits the exhaust. Not only does this displace any standing water and coat the water jackets and heat exchanger with a corrosion inhibitor, but at the same time it distributes the fresh, clean oil that was entered earlier, which will prevent internal rust during storage.
While you could wait until your next trip, now is a good time to check zincs, belts and electrical connections, as well as the O-rings on fuel fills. Also inspect the physical connections at the transom and along the exhaust outlets — lots of water flows through here!
Replace, repair and service anything that looks suspect or worn and you’ll have that much less to do on your next trip.
Seal the exhaust outlets on the hull and air filters on the engine. This prevents moist air from the water finding its way into the combustion chambers via open exhaust or intake valves, while the engine is enjoying some well-deserved downtime.