I have a 1977 Mercury 75/7.5 hp, 2 cyl, 2-stroke. We call it "the engine that think it can!" She is a beautiful engine thats on our 13 ft Gregor...
She works great. I cleaned the carb and tuned her up. Her idle isn't too rough.
After about 1 to 2 hrs of continuous running time, she starts whirring... not in idle but when at 1000 rpms or higher in gear or not in gear. Its puzzling to me because I can't really start to take it apart when we are in the middle of the lake or behind the break wall.
I do have a subscription for this engine to Seloc Online if needed.
Any ideas on where to start trying to narrow it down?
Thanks in advance!