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88hp ideling problems

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walkinsick

New member
still can't get this motor to idle, so I took it to the shop. I was told the bottom crank seal was bad and that was causing my problem. I pulled the power head and found the gasket between power head exhaust adapter blown. could this really be causing all my problems. crank seal looks ok but will probably change it anyway. thanks for all the help, I really appreciate it.
 
Unlikely that base gasket is causing a idle problem but it's good you came across it. Also unlikely the bottom C/C seal is affecting the idle but as long as the powerhead is off, change it for peace of mind.

What is the model number of that engine?

What are the compression readings of all cylinders?

With the spark plugs removed, the spark should jump a 7/16" gap with a strong blue lightning like flame.... a real SNAP! Does it?

Spark plugs should be Champion plugs gapped at either .030 or .040 . Performance varies on some engines with the different gaps.

Exactly what kind of idle problem are you having?
 
to answer your questions, it is a 1988 johnson 88hp spl. compression ios 125+ on all cylinders. spark will jump 3/4 inch gap with a real snap. carbs have been rebuilt then replaced. all hoses have been checked and replaced as needed. motor just won't idle and runs very rough. didn't understand how exhaust could be causing the problem, i'm new to 2 cycles. am hoping this fixes my problem but i have my doubts.
 
To contradict myself...... If the powerhead base gasket was broken in such a manner whereas the exhaust was allowed to travel into the top motor mount area, it's possibly that the cowl opening just under the bottom carburetor could draw in the exhaust gases which would affect the rpms obviously.

In all my years in the marine line, I've never seen this take place BUT it could happen. Let us know how the gasket replacement works out for you.
 
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