Few things spring to mind.

one is your own suspicion about where the oil pick up might be in relation to the oil level now the engine is upright, easy enough to check and modify.

one point five, (i reckon this is the kiddie) is the oil draining back down into the sump fast enough, again due to drain holes not being quite where they should be, fit an oil pressure gauge and experiment with oil levels.

two is how is the engine held in place, is it on rubber mounts to soften vibration as it would be in its designed car siting, or is it bolted solidly in place, if its the latter that could feasably allow too much vibration and the camshaft can't take it.

third, is the cooling system up to the mark, presumably the engine is working harder continually driving a propeller, so may require additional water cooling, and possibly an external oil cooler radiator.

fourth, as the engine is working harder and hotter (i think it will be) is the oil good enough.

fifth, are you overevving it.

Edited by gordonbennet on 27/09/2014 at 13:04

Is the resistance of a prop in water (a bit like a torque converter I suppose) greater than a propshaft driving wheels firmly connected to the ground? So what about the radiator?

I expect a prop churning in water, could send shock waves back through the d*****ine* to a degree found in something like rallycross.

We don't know what sort of cooling is involved here, if the boat is going into salt water i expect it's running a radiator and self contained cooling system.

Be interesting to hear the end result of this problem.

*why on earth would the auto censor worry about drive line, or is dri vel a banned word, if so the vast majority of politicians would thankfully never be heard here.

Edited by gordonbennet on 27/09/2014 at 20:36

Good idea to try extra oil. im just a bit unlucky i guess. will let people know the outcome soon.

Don't forget that an overfilled diesel engine can start burning its own oil ....

Edited by Andrew-T on 28/09/2014 at 00:29