right engine 4lha ste not running right

I recently took my 390 with twin yanmar 4lha ste out. I noticed that I had no volts indicated, low oil pressure, low engine temp and the engine lagged behind the other (starboard). I came back to the marina and shut everything down. I waited a few minutes and started both engines. Both are now running perfectly! What kind of issue did I have? My boat is a 2000 so they are not electronic. Seems electrical. Alternator is putting out volts and fuel solonoids are ok.

Sounds like each engine is drawing from it's own fuel tank. I would bet there are screens on the poorly performing engine intake line. Rust and scale temporarily plug the screen. When you shut the engine down the rust and scale falls off the screen.

If you can get at the screens, remove them. Let the Raycors catch the rust and particles, that is what they are there for.

Diesels do not need electricity to run, although some of the newer ones are somewhat dependent on electricity I doubt if that is your problem.

pete