Top Ten General Marine Diesel Engine Do’s and Don’ts

lagoon 380 marine diesel engine

  • Don’t start engines without checking fluid levels, belts, and raw water inlet.
  • Do not permit engines to sit without running them for more than 7 days – try to operate engines at least every 5 days.
  • When running engines, allow engines to warm up, then run at about 1500 RPM for about 5 minutes, then shut down.
  • Properly lay up engines that are not going to be used for periods of greater than 30 days. Long periods of disuse result in serious internal engine rusting of cylinder walls and valves.
  • Start engines with throttles in neutral. Do not race engines until they are up to normal operating temperature. This is very damaging.
  • Avoid prolonged idling if possible, this can glaze the cylinders. Always run the engine at cruise speed or higher on the way home for at least 30 minutes to dislodge carbon deposits.
  • Service fuel system immediately if excessive exhaust emissions occur.
  • Always put the engine into forward and astern before casting off to make sure that your gear selector is working properly.
  • On a catamaran, always start the engine farthest from the helm so you can hear that it has started to avoid running the starter with the ignition once the engine has fired.
  • Always wait for the RPM to drop back to idle before changing gears from forward to astern or vice versa.

Engine maintenance should become a habit. Make a list of the things to check and diligently go over every item before you leave the dock.

This article, “Maintenance Fundamentals” by David Pecoe is great for reference.

Another great article by Tim Bartlett “Diagnose and fix marine diesel engine problems“.


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4 thoughts on “Top Ten General Marine Diesel Engine Do’s and Don’ts”

  1. It was really interesting to read about how it is best to run diesel marine engines at least once every week. Would it be a good idea to clean the fuel tanks out at least once a year as well? It seems like it would be important to make sure that foreign objects and grime get stuck in the tanks.

    1. Tom, we don’t clean our tanks annually unless we know that we may have water/condensation in the tanks or if we took on bad fuel.

  2. Thanks for explaining that it would be smart to check your engine for fluid leaks. That is good for me to get an expert to do the inspection for me. Especially since it seems like they might be hard to find.

    1. Estelle Cockcroft

      Emily, yes it is good practice to do that every time before you set off. Incidentally, that is how we discovered that our saildrive had to be replaced. Stephen noticed milky oil in the saildrive during his routine checks. We had to haul out the boat and it saved us a lot of trouble.

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