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Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 3935
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
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I have a 13' foot whaler with a 50hp Yamaha 4 stroke.

Customer Question

I have a 13' foot whaler with a 50hp Yamaha 4 stroke. Previously we had a 2 stroke yamaha 50hp and we bought a new engine because it continuously bogged down under load. It would run fine at idle or with very light load. I bought a new 4 stroke engine and it is doing the same thing. We have tried everything, new fuel tanks, lines, cleaning the filters and bleed valve but it always happens.... any idea what the problem could be?
Submitted: 1 year ago.
Category: Boat
Expert:  Charles replied 1 year ago.

Hello, my name is***** will assist you.

The one thing that you have not looked the should be addressed is the prop on the engine. If it is too much of a pitch, the engine will not be able to reach full operating RPM. On the four stroke, this is over 5500 RPM.