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Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 3929
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
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My 2006 250 4 stroke Yamaha boat motor runs great hour at

Customer Question

my 2006 250 4 stroke Yamaha boat motor runs great for an hour at any rpm on the water....then all of a sudden it wants to hesitate and not run over approximately 3200 rpm ...if I let the boat set over night it runs great for that first hour again....whats up?
Submitted: 1 year ago.
Category: Boat
Expert:  Charles replied 1 year ago.

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

Your problem sounds like one of two things. Either the engine is getting hot, activating SAFE mode and you just cannot hear the warning horn, if it has been a while since your last cooling system service, I would have that done. The other problem could be that you are running low on gas on the engine. This could be if the boat has been sitting and the fuel system is varnished up. To correct this, you would need to remove and open the vapor separator tank on the side of the engine. Get a good quality carb cleaner and clean out the inside of the VST, and the filter there.