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Mercury 98 running at half throttle

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cdevaro

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" My 9.8 HP Mercury starts run

" My 9.8 HP Mercury starts running good and runs good for about 10 minutes, then bogs down to about half throttle. I've had the carberator cleaned and rebuilt twice, but no change. Any suggestions? "
 
Carburetors are often cleaned

Carburetors are often cleaned for no reason. Do a compression check. And check that a spark will jump a gap of 3/8" any less is not acceptable.You may also have an open reed valve which is harder to find.
 
" check the primer bulb on the

" check the primer bulb on the fuel source it will cause a restriction if it isnt holding a prime as well and the fact you say it runs for 10 min discounts the reed valve or carburator or spark, those are fine also if it is a portable tank check the vent screw to be sure it is open also check to be sure the engine doesnt have something wrapped arround the prop shaft that is heating up and expanding causing a high load on the propeller

sounds to be a restriction BEFORE THE CARBS not after "
 
" The vent screw is opened and

" The vent screw is opened and if the primer bulb goes down, I pump it up but no change in the way it runs. If I shut it off for several minutes, it still does not run at full throttle again until the next day when I take it out again. Someone suggested it may be the coil getting hot. I really don't know. Does this sound like a possibility? "
 
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