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Fuel slick behind my boat

T

tim_sunfish

New member
"I have a 94 25TEERC Johnson.

"I have a 94 25TEERC Johnson.

Starts and idles beautifully, other than the smoke and fuel slick..also it will cuts out at higher RPMs fouls my plugs and sucks gas like a pig. The bulb will sometimes collaps as I run across the lake. At home she drips a little of that blackened unburned fuel from the exhaust at the prop.

I'm hopping I can fix this as it sounds like a leak from the fuel pump into the block, or a weakened gasket in the jet tube.. Worst case is I have a crack in the block.. No cracks visable, no oily mess on block.. The crack maybe inside..??

Thank you for any help you may provide guys
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"PS... Would there be a chance

"PS... Would there be a chance that the fuel primer "at the block" not the bulb primer.. somehow has a leak allowing that extra fuel to be drawn into the crank case??? As I said, it runs & starts beautifully other than the smoke, wet fouled plugs, and fuel slick, collapsing bulb, and it does cut out at sustained RPM..due to wet plugs my guess.. electronics are okay."
 
"Tim, if I was guessing, and y

"Tim, if I was guessing, and you had address all the other possible issues (fuel pump, carb) I would suspect that perhaps you have a chipped or broken leaf valve (reed) that would be allowing the extra fuel to be "sucked" into the cylinder.

Although that wouldn't be the first thing I would check out - but if the carb has been cleaned/rebuilt - fuel pump is ok, all else has checked out good - that's something to consider and check..."
 
"Thank you for the reply Graha

"Thank you for the reply Graham.

I have just replaced the needle & seat & float. This seems to have reduced the slick a lot, as well, there's no more drip from the exhaust while parked in the driveway. I believe the float is now just a touch low..will reset.. Also there is a wrinkle in the diaphragm that bugs me. Will drop the $60 for a new pump after I see how well things go once I have the carb adjusted.

Thank you again, a great site & very helpful people here."
 
"A broken reed valve will NOT

"A broken reed valve will NOT allow extra fuel to be sucked into the crankcase, it just is not so. It means there will be no crankcase compression and the motor will perform poorly on that cylinder. Get the motor started and isolate the fuel primer ( disconnect it ) and see what happens."
 
i have a 89 40hp that was leak

i have a 89 40hp that was leaking-using gas. 6 gallons in about 9 miles. my proplem was the fuel primer (choke) on the block went bad. got one on ebay at a real good price.
 
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