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90 2-cycle bogging

HBMSkip

New member
I recetly purchased a used outfit that included a 2004 Yahama 90 hp 2cycle that had been sitting for some time. (A "bargin" I could not refuse.) The motor starts slowly, but then runs well, but only briefly. After 10 min., more quickly at full throttle, or so it bogs down and will not turn over about 2000 rpm or less. It also ran hot when I fiirst purchased it, but after I replaced the thermostat and impella it no longer overheated. In any case, when it boggs down it will not run well again until it has had a chance to "rest" and then it briefly runs well again. Any ideas would be appreciated.
 
Assuming the compression is good and the carbs are clean. When the engine is running you need to check the cylinder head temp. Make sure it is coming up to temp.
 
If it sat with fuel in the carburetors you will need to confirm that they are clean.---------------Also verify that the oil pump is working and delivering the correct amount of oil.-----------All conections on fuel system should also be checked.
 
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