1. Per the original post, is it possible I am just blowing out carbon buildup in the system from my low rpm runs? Is it dangerous to the engine to run with the black exhaust water to test the theory?
2. Everywhere I look online says Yanmars DO want to be run at 80% of max output which would be 2720 - are you saying that is wrong??
3. The PO installed the folding prop and didn't have this problem.