I have a small 21hp Universal Diesel in my sailboat that will start
only reluctantly with a shot of starting fluid. The batteries are
strong and the glow plug is working fine. Even after it has been
running for a while and the engine is good and warmed up, I could shut
it down and it still won't restart without the starting fluid. It
seems to run just fine once it gets going with all the power I'd expect
from an engine that size. Anyone got any ideas what the problem might
be here?