carburetor leak

Tue Jan 15, 2013 11:40 pm

Hi All,
My carburetor is leaking at the choke shaft, right at the choke lever.Can I assume that if I replace the felt seal and the brass press in washer that comes in a quality carb rebuild kit that I will be able to stop the leak or at least slow it down significantly? Any input or advice appreciated!
Greg
(Greg49)

Re: carburetor leak

Wed Jan 16, 2013 12:07 am

Greg, I can't visualize how the gas level would be getting high enough to come out the shaft seal. I don't think the felt was ever intended to be a liquid seal. On the bottom of the carb is the plug with a felt disc under it that allows excess gas to drip out. I wonder if you have a needle valve/float issue.

Bob

Re: carburetor leak

Wed Jan 16, 2013 6:10 am

Yeah, surely a float problem or trash in the needle not allowing it to shut fully off. Don't pound on the carb, just a little can bend them. Probably need to start at the fuel strainer and see if there is any trash in it. If so start there and work your way to the carb. If it won't flush out, then you'll need to take it apart and clean it.
A little bit of leakage, especially if hard to start is normal while trying to start. If you have to take the carb off, be careful not to break the idle tube.

Re: carburetor leak

Wed Jan 16, 2013 6:57 am

Just my two cents. Those who have spent time around the Cub engine know that most carburetor needle valves will leak slightly when the engine is off. This slight leak will not affect the performance of the running engine, but can cause some to believe they have carburetor problems. Standard operating procedure should include shutting off the gas tank valve whenever the engine is turned off for extended periods of time. I am not saying it is impossible to achieve a leak proof needle valve set up, but it is my opinion that the time wasted in doing so is not worth it. Just shut your tank valve off when you shut down for the day and accept the fact that this goes with the territory.

Re: carburetor leak

Wed Jan 16, 2013 7:58 am

Bob McCarty wrote:Greg, I can't visualize how the gas level would be getting high enough to come out the shaft seal. I don't think the felt was ever intended to be a liquid seal. On the bottom of the carb is the plug with a felt disc under it that allows excess gas to drip out. I wonder if you have a needle valve/float issue.

Bob

Bob, we went through the needle valve, float area, a couple of weeks ago, and stopped the "leaking when not running" issue. This is a newly developed problem. Ed

Re: carburetor leak

Wed Jan 16, 2013 8:27 am

Greg,

I'm having a hard time understanding how fuel could be leaking from the choke shaft openings without being visible from several other places. Namely the weep hole and the air cleaner inlet hose. In order to reach those openings, the fuel would have to be awfully deep in the throat. I suggest disconnecting the air inlet hose and see what you find. My suspicion is that it is coming from somewhere above, and seeping down to the area of the shaft. Let us know.

Image

Re: carburetor leak

Wed Jan 16, 2013 1:20 pm

Don, It must be filling up with gas to do that , I think a faulty mechanic :D I mean doughnut eater

Re: carburetor leak

Wed Jan 16, 2013 1:56 pm

The weep hole must be plugged. I am working on a member's carb that the PO had plugged the weep hole with a sheet metal screw because it "leaked" too much. You should have seen how much fuel got caught up in the intake side of the carb. So much that it stalled the tractor! Sometimes I just don't know what PO's are thinking!!!

Re: carburetor leak

Wed Jan 16, 2013 2:57 pm

Gentlemen,
I know what I posted about my carburetor seems far-fetched.As Ed (Scotty D's Dad) had posted, we had taken the carb apart together, made positively sure that it was very clean, Tested the needle valve and seat, and checked and adjusted the float.
I took it home , installed it , and it worked fine.I had also cleaned the sediment bowl and screen prior to all of the above.Two days later, I started up the cub, and saw that it was not leaking from the bottom as it had been, but now from the area of the choke linkage.I put a finger under the linkage and got a constant drip.Am I out of my head?
What I plan to do now is make sure the carb is totally dry of fuel on the outside, then sprinkle some baby powder on it, start it up, run it , shut it down and observe where fuel shows on the powder first.Again, far fetched , but I believe it will show that fuel is coming from that location.Next move? re-evaluate the float setting again.I do not believe Ed's mechanical skills are at all deficient.I WILL GET to the bottom of this.(hopefully with his help.)
Greg

Re: carburetor leak

Wed Jan 16, 2013 3:00 pm

Take the breather pipe off and then check it
Boss

Re: carburetor leak

Wed Jan 16, 2013 3:08 pm

Leak gasoline or condensation?

As others have suggested, remove the air cleaner tube. If there is fuel dripping from the choke control shaft the air cleaner tube will be full of gasoline. If carburetor throat and air cleaner tube had that much fuel, tractor wouldn't start or run.

I'm going with condensation.

Re: carburetor leak

Wed Jan 16, 2013 5:17 pm

OK.I've got something to go on now.Thanks all! I will inform everyone of my findings.
Thanks again.
Greg