I have a Yanmar 3JH4e engine from 2006. Returning from a breezy daysail yesterday it wouldn't start. Engine worked fine earlier during the day, no strange noise or smoke, normal speed and revs.
When i try to start the engine it cranks slowly but doesn't start.
I think i've checked the most obvious things. There is fuel in the tank, the start battery is charged and tested, engine oil looks good, no dirt in primary fuel filter and i've bled the fuel system.