Well done
@JBP-PA . That is the first offering here with a positive theory behind it. What else could have changed over the period of engine replacement while the boat was in the water ?
And this is NOT a fouled prop :
That one statement is what has always made me believe that fouling was NOT the problem here. One year and one year only, we all had a bad fouling problem in our marina over the winter. I was scheduled to move my boat over to the crane (annual half haul out) and almost got lynched by the marina mgr. for the amount black smoke I belched out in the 300 meter run over to the crane. He thought it was a boat fire and was about to call the fire dept. I could not get over 1200 RPM at WOT and was barely moving. When we were finally out of the water, the prop looked like a basketball it was so heavily covered. Smoke from a fouled prop is something you will not believe until you've sat in the middle of it.
@Night Watch , if you can't find any ID metal patches on the back end of the engine for ID, please unload the engine (if you have unloaders) and roll the in-gear engine over exactly once and note exactly how much the prop shaft rolls over. This is your gear ratio.
Right now, I'm betting all I have (which is pretty much squat at this time of year) that this is your answer.
