Carb leaking and generally doesn't seem quite right

Hi

So, I have a 52 side mount, with MS carb. Just rebuilt engine, rebuilt governor, replaced fuel shut off bowl contraption, bought rebuilt carb, replaced wiring (except plug wires). Was running okay, still didn't seem perfect, then I shut her down for a few weeks. When I came back this weekend, found out I had left the key on. I got her to run, but only with choke pulled out, which I took to mean I about killed the points. So, ran it for a little bit, then she struggled even with more choke, so shut her down for the night and replaced points/condenser this morning. Ran her for half hour to hour or so. Still wasn't seeming quite right, and thinking maybe some bad gas, I went to get more gas. When I got back, gas was leaking from the carb. I swapped that carb out for my old carb, ran it another half or full hour but then when stopped saw gas leaking out of it. So, I swapped back to the newer carb, and pushed the metal fuel tube up a little bit (as I thought I pulled it down some when swapping carbs). Instead of wait to see if this was going to leak again, I just got her running and mowed the rest of the yard. About an hour into it, seemed like the rpm's started dropping, then up then down. Not terribly bad, but didn't seem right. Then I shut her down. When I shut her down I turned the fuel off and let it die out, so that I wouldn't have to deal with leaking fuel, assuming it was still going to leak. I could hear air bubbling in the gas tank once it died (maybe normal, I don't usually shut her down this way) .It was also leaking what may be gassy oil at the oil line convergence area behind the exhaust clamp. I'm thinking maybe I got gas in the crank shaft and that's why this connection is leaking all of a sudden. Smelled like gas, but so did my hands, so not 100%, nor was oil level excessively high (or noticeably higher).

So, any thoughts on what I should tinker with next? I saw online that leaking carbs are typically stuck needles, etc, but just seems odd it would happen with two carbs in a row, granted the second one was not restored yet.

Thanks for any suggestions!

MY Two Cents
i have seen to may carb fuel inlet needles leak lately... may be to the gas we use to day???
usually will flood the crankcase with gas and dilute the oil..not a good thing..so always shut off the gas when not used..i would take the carb apart and inspect,the needle ,for wear and turn carb upside down so the weight of float will keep needle close and with a small hand vac/pressure gauge pump .pressurize the fuel inlet fitting..it should hole 1 lb psi or so..if it does not you need to replace the needle and re educate the seat.some seats are replaceable...

Sounds like a couple of problems.

The leaking carb is either the float set too high, problem with the needle and seat (worn/damaged), problem with the float (sunk, bent) or, most likely, trash under the needle preventing it from shutting off the gas flow. Is the filter screen good and in place? How is the tank, rust or contamination? It doesn't take much, a tiny speck can cause the carb to flood. Sometimes you can simply shut off the fuel and run the carb dry, then turn the fuel on and it will flush out the debris.

The bubbling in the tank... That is a very good clue. It is one of 2 things. Either the cap is not vented, causing vacuum to build in the tank, stopping the flow of fuel to the carb. Or the tank or fuel line is getting too hot and fuel is boiling. Is the fuel line routed as far away from the exhaust manifold as possible? Were there any heat shields between the tank and engine? Are they in place? If the tank or line were boiling and pressurizing, that could contribute to the flooding, but still goes back to a tank vent problem.

The oil leak... Not sure what to say, just need to fix it. It's behind the exhaust clamp? How close? Any way to move it further from the exhaust heat? Insulate it?

Thanks for the replies! I think its just crap in my gas. Carb was freshly rebuilt, so would make sense that junk in the gas would cause this, vs some major issue.

And the gas cap seems like it should be vented, but doesn't seem like it. Always pressurized when I open it. Pretty sure fuel wasn't boiling!

And oil leak, was thinking if gas mixed with oil the lower viscosity mix caused the leak, but still leaking after oil change, no big deal here, thats simple.

Glad to hear it doesn't sound like I have major issues!



Thx

co uld be the long stem nail type air needle valve is missing the seat because it is slightly bent ,,, never liked a ms carb for many reasons ,but to be honest never had a real good one ,all worn out , ,seemed like they guzzled gas and slobbered a lot ,, this springair needlethreads stripped out on my 730 Case marvel /scriebler , I put a zenith carb from a Dc I had, that 730 never run as good as it does now ..