Mercarb 2bbl dumping fuel >1000rpm (visible drops/flow, not spray)

[funk6294]

Re: Mercarb 2bbl dumping fuel >1000rpm (visible drops/flow, not spray)

If its dumping fuel out of the ventures then the fuel level is too high in the float bowl. Four things can cause this... incorrect float height, bad float, bad float needle/seat, or high fuel pressure forcing fuel past the float needle. If I was to start some where I would check the float height and ensure it meets spec. Next would be to consider replacing the float. There generally inexpensive and can become saturated with fuel reducing bouancy and causing the fuel level to rise in the bowl. When running at idle you should not have fuel coming out of the venturies.

 

[chimmike]

Re: Mercarb 2bbl dumping fuel >1000rpm (visible drops/flow, not spray)

I've seen that the composite floats can become saturated like you said. As you also said, they're inexpensive.
Certainly 3 things I will do to try to combat this:
1) new float
2) New cap/rotor
3) New plug wires

I've thought about the bad compression, but even still, it's satisfactory on at least 6 of the cylinders, and the compression was done before I'd even gotten the motor running, was still on old oil, etc. Could've been a sticky valve, etc. Though, no guarantees the headgasket is okay. When I re-do the floor of the boat this winter I will likely pop the heads off and see what's going on in there.