Logo
FULL SITE MENU

My mechanic is stymied on 99 4 stroke

T

terryfix

New member
"We both need your help! A 199

"We both need your help! A 1990 Yamaha 9.9 4 stroke starts and runs smoothly, but bogs out with no increase in r.p.m. at all when the throttle is turned. A dealer mechanic insist that it is the intermediate jets and is rebuilding the carb for the third time. Does anyone have any insight? He's a great Evinrude wrench, but should I take this to a Yami specialist? I dont want to insult him."
 
"I have seen this condition al

"I have seen this condition also to be a result of a life of slow trolling and running a bit cool, causing excessive carbon build up in exhaust chamber. This results in the exhaust gasses being very restricted - no place to go, and gives simptoms of carb jets plugged or restricted or frozen timing. If the exhaust can't get out fast enough, the engine will not go past the RPM that will let exhaust gasses out."
 
"Thanks for the info, Jim. I h

"Thanks for the info, Jim. I have the engine back and the mechanic says that its fixed, although I have yet to run it. Carbon makes sense and I've used a spray called "Engine Tuner" by Evinrude on other engines, to remove deposits, with great results. This Yami is due for a good dose of Engine Tuner and Seafoam. I will post results later. Thanks also to all of the pros that take time to help those of us struggling with the mysteries of the outboard."
 
Back
Top