I recently bought a 1991 sweetwater 24' pontoon boat with a yamaha 1991 85HP motor. I took it to the lake and after half-trottle it would not gain rpm, then after 5 min the heat alarm would go off.. I went through everything on the motor and it "seemed" ok. Then I looked at the prop and noticed it was a 13.5 x 16. I dont have a tach to read the rpm's. Does that seem like a prop problem? Seems logical that the motor cant pull the prop therefore it gets some rpms then cant pull the high pitch prop. Any advice would be nice! Or do I have a motor problem? Btw its a 3 blade prop.
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