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I have 1992 40HP. evinrude motor start up fine when idleing top cyl. cut in an out
get around 1500 RPM motor runs grate any idears
get around 1500 RPM motor runs grate any idears
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Remove spark plugs. Plugs should be Champion QL77JC4 plugs, gaped at .040 (hot Spark) or .030 (long life).
Check compression... what are the psi readings of all cylinders? It should be in the area of 100 psi and fairly even on all cylinders.
Check that spark jumps a 7/16" gap with a strong blue lightning like flame... a real SNAP! Does it?
If the two above areas are as they should be, the problem is usually within a carburetor.
NOTE: A slow surge (up/down) in rpms indicates a fuel problem... a sharp fast surge indicates a ignition problem.
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