Re: 18hp h2o in bottom cylinder

[johnyrude200]

Still doing some investigation. I pulled the exhaust bypass a 2nd time (drilled 2 holes in the lower cowel so I could get at the 2 lower screws without pulling the powerhead a 2nd time) and also pulled the cylinder head. I used a drill gun to turn the motor over at a reasonably high speed (whatever the drill gun would turn…I would assume around 200-300RPM).

Observed water flow up through the bottom of the powerhead, the usual spots. Replaced the exhaust bypass plate and repeated, did not see water getting into the cylinders. Replaced the cylinder head and repeated, did not see water getting into the lower cylinder.

It does appear that the bottom cylinder is very wet with fuel mix, so I’m going to pull the carb a 2nd time and take a closer look at the manifold. I guess maybe a leaf plate is distorted and it might be flooding badly? Will report back shortly. The top cylinder is burning as it should, bottom is soaked when I pulled the plugs (as in, plug was very saturated and wet).

Yes it’s been recurring, only started on working on this motor yesterday and it has a 100% fresh ignition system (nice 1/2 spark both cylinders), and I went through the carb, so now I’m moving onto other aspects. At this point there isn’t much left on the motor that I haven’t touched yet. I don’t think the fuel pump is leaking fuel through the diaphragm because it sits on the top cylinder (separate fuel filter setup type pump), and the bottom cylinder is the one that is soaked/wet/not working right.

While running the motor it’s a hard start, even when timing is advanced to the highest neutral setting (not WOT). Once started if I shift to forward quickly, I can get to WOT, but it sounds like it’s intermittently picking up the bottom cylinder and only running off the top cylinder. It clearly does NOT have the power that it should.

I’ve already switched plugs out with a new set to rule out a bad plug.