Often, when sitting for a long time, especially cold weather
, gas engine
rings shrink and no longer make a tight seal. The engine won't start because the compression
is so low. If you take a compression
test the values maybe 2/3 of normal.
Squirt engine oil
in each cylinder rotate the engine a few turns, and compression will probably be close to normal. If not you probably have bad valves. Usually after the oil
, the engine will start, smoke for awhile, and if run up to operating temp will reseal the rings.
My experience with gas engines in a marine environment
that have sat, usually need a new condenser. Best bet for gas engines is put on electronic ignition.
If the engines start, I'd operate the boat a few hours before jumping into major repairs
. Bores, valves, etc.
There should be books
available on your engines.