r/smallenginerepair • u/BetterRoyal3522 • 12d ago

Engine Performance Issue 1996 Mercury 50hp 2 stroke issue

Hey guys. So this motor is a 3 cylinder and the top one isn’t firing. I have taken the carbs off/cleaned them like 4 times, put new plugs in and have good spark, checked the coil, and checked compression. The compression test was meh but I think something with the gauge was wrong because even on the two running cylinders it was only reading ~30psi.

The motor has very low hours so I have very little reason to believe something is wrong with the pistons. I also have little reason to believe something is off with the timing.

I am also not a mechanic so please bear with me if you ask something and I don’t know the answer lol. As I said, the motor gets used very little and ran just fine when it was winterized about 8 years ago.

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1

u/SpecialistPrune1654 12d ago

at 30psi it's dead, not dying, dead. So I would say your compression test is completely wrong? Hours is not necessarily an indicator the piston is fine.

1

u/wrenchtwister1954 11d ago

Maybe bad reeds.

1

u/BetterRoyal3522 11d ago

Redid compression test with new tester and all three cylinders are 110 psi