Re: Water Getting in Top Cylinder Yamaha 40hp Twin

[Don]

Well, the big thing to worry about is if the flywheel key sheared….And, the only way to confirm/rule this out, is to verify TDC with a dial indicator or the OMC TDC tool. If the flywheel key had sheared, chances are the timing would be retarded causing poor idle and lack of WOT power. Again, this situation is not something you could verify with a timing light. I hear what you are saying, you did not alter any of the original adjustments, but who knows what may have happened since it initially ran nicely after the rebuild…
THANKS for the lead on the affordable bore scope, sure need one of those! Funny how I used to be able to look in the cylinders with a little flex light and be able to see scores/scuffs, those days have sure passed me by!