1998 Mercury 40 hp - no compression on 1 cyl

1998 Mercury 40 hp - no compression on 1 cyl, how bad of a scenario could this be? I don't have much information on the motor, but was wondering how big of a fix it might be (obviously depends on what the real problem is).

JL8Jeff said:

1998 Mercury 40 hp - no compression on 1 cyl, how bad of a scenario could this be? I don't have much information on the motor, but was wondering how big of a fix it might be (obviously depends on what the real problem is).

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You almost answered your own question. LOL It could be something simple as a head gasket, albeit it would have to be severely blown and you most likely would hear it whistling if that when you spin it over quickly. With 0 compression you almost have to expect the worst and if not be pleasantly surprised if it isn't.

no compression? sounds like the compression gauge wasn't attached correctly. Unless it sounds like a punch of bolts rattling around in a coffee can there should be some compression.

onthewater102 said:

no compression? sounds like the compression gauge wasn't attached correctly. Unless it sounds like a punch of bolts rattling around in a coffee can there should be some compression.

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not unless there is a hole burnt in the piston, which isn't too uncommon on 2 strokes

I would pull the plug and look for aluminum on it