Re: 90 Marathon 2 Stroke no power in bottom end
hms11 is on the money. Your engine is not going to be that great with that compression. The wet compression is not a valid test on a horizontal cylinder as the oil is not going to be able to seal the rings as it does on a vertical cylinder.
As you will be aware the 2 stroke engine needs to produce crankcase pressure oscillations in order to drive the fuel pump and transfer fuel from the crankcase to the cylinder. If there is sufficient blow by you may well be interfering with the rhythm of the oscillations causing a momentary lapse in fuel delivery.
If everything else checks out (including the driven clutch not being jammed open) then I too see a top end rebuild in your future.
Dave
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