91 Marathon 2 Stroke Carb Leak

[dzig_33]

Had a friend tell me her 91 2stroke was running rough and backfiring, she wondered if I would take a look. Throttle butterfly shaft bushings were gone and body was wallowed out where the shaft sits. Gave her a couple of site sponsor names and numbers for a new carb. Don't know which one she got it from. I got it from her, looked it over, set the idle mixture screw and tightened it down. Bolted it up, linkage back on, cranked it over and no go. Gave it a huff of starting fluid and it fired, so I knew I had not somehow screwed up the ignition. Took a piece of fuel hose, pushed it on the fuel inlet, no blow. Took the carb back off, unstuck the needle, neither needle or seat looked damaged, looked at the float level, looked ok. Bolted it back up and wahlah, running cart. Looked like all was good. Was going to take it back to her after a day in my garage, smelled gassy. Carb bowl wet and dripping. Took it back off, set float level by the manual, tweaked it just a bit. Blow test was good, back on the cart, same thing, damp bowl after running then setting for a bit. Ideas are welcome.

[TomStark]

any chance there is an issue with the bowl gasket?
Tom

[dzig_33]

Bowl gasket looks good, I might try swapping with old carb gasket

[dzig_33]

Finally got a chance to look at this again. Cart wouldn't run, gas coming out of exhaust pipe, into the air cleaner hose, dripping off the carb bowl, but nothing coming out the vent on top of the carb. Do I start with fuel pump, float needle or reed valves? Any other ideas?

[TomStark]

Reed valves would have nothing to do with this. Since you are having in such issues, I would pull the carb and go through it. Check everything trust nothing. If it is dumping gas, it is not the fuel pump, that does not make enough pressure to force a leak. You have a carb issue, and you need to check everything, all gaskets, float level, float weight, needle and seat, etc.
Tom

RIT rocks, cancer sucks. sent from my S5 by tap a talk

[dzig_33]

Back on it again today. Took carb off, a couple of jets had backed out (the one in the plug that holds the bowl on and the one in the tube in the middle of the carb. Checked float level again, looked ok. All back together, runs great. Gas now spewing from carb vent, especially from high rpms to low rpms. What now?
Thanks for the responses.

[TomStark]

I don't know, but would guess that the float level is just slightly high, or if the cart is lifted perhaps there is enough angle to make a normal fuel level a bit high. I have seen some slight overflow on my carb, but not much, and not all the time. I plan on adding EFI so I do not plan on messing with the carb since it is really not a problem

RIT rocks, cancer sucks. sent from my S5 by tap a talk

[dzig_33]

Wow, never had a carb so sensitive to float level settings, took 4 times off and on today to get to where it would get gas fast enough to keep running, but not so much that it would pressure up and spew out the vent. Hopefully it stays running for her. Looks like next on her list had better be a drive clutch. Hers stays open til it spins up, then slams shut, oh well. She can drive it for now. Thanks for the replies.

[TomStark]

Originally Posted by dzig_33

Wow, never had a carb so sensitive to float level settings, took 4 times off and on today to get to where it would get gas fast enough to keep running, but not so much that it would pressure up and spew out the vent. Hopefully it stays running for her. Looks like next on her list had better be a drive clutch. Hers stays open til it spins up, then slams shut, oh well. She can drive it for now. Thanks for the replies.

If you really like her, you can offer to take that drive clutch apart and clean it up and make it work better! But you need to REALLY like her! LOL!
Tom