Unusual Carb Leak

Sat Apr 24, 2004 7:30 pm

I've been working on a 1949 Cub I bought a while back and trying to get it read for grass cutting season.

The carb was leaking and I decided to rebuild.
I got a carb rebuild kit and rebuilt it and thought all should be fine, but it still leaks in the same place.

It's leaking from the choke shaft in the carb onto which the butterfly valve is mounted. It leaks from both sides.

This is the shaft that the choke rod is connected to that flaps the butterfly in the air intake passage.

It's like the seals around this shaft on both sides are just worn out.

Has anyone seen this? and does anyone have any suggestions. I sure appreciate the help.

Sat Apr 24, 2004 9:13 pm

If it's leaking gasoline around the choke shaft you have a serious flooding problem. There shouldn't be any gas at the choke, much less deep enough to leak around the shaft. Assuming this is only after it has set for a while, the float is probably not closing the float valve and allowing the carb to overflow back into the breather pipe..

Sat Apr 24, 2004 9:13 pm

If you bought the carb kit from Case/IH, the kit of choice among farmallcub.com members, the seals for the choke shaft and the throttle shaft should have been in there. If so, did you replace them :?: Also, you may want to check the float level....sounds like to much fuel is getting into the carb. Lurker Karl is a good source for carb info.....he will probably post a reply as well. :wink:

Re-Checked Carb

Mon Apr 26, 2004 7:31 am

After checking the information in the FAQ and Rudi's excellent manuals online, I took my carb apart again and had a look at the float travel. The book says it shoud only travel 3/16" and mine was easily going 1/2". I carefully bent the tang to reduce the travel and now is set at 3/16".

I ordered my carb kit from Wenger's but will get my next one from Case IH. I rode out to my Case IH dealer in Wilmington this weekend, and picked up a few things.

I'll report back how it looks. I'm betting that fixed it.

Thanks all,

Thu May 13, 2004 8:25 am

Just an update on this.
I followed Cub-Bud's advice and got me an IH carb kit and then built me one of those U shaped tube devices to check the level of fuel in the float bowl and it worked like a charm. See the picture here http://www.metrotone.com/20040507_Grace_Haley/slides/IMG_2720.JPG.
My 1949 Cub doesn't leak a drop and it cranks up on the first turn and purrs like a kitten.
Thanks to everyone for your help. I hope I can help someone some day.

Thu May 13, 2004 11:49 am

:P _ Dave, Glad to hear everything worked out good for you.

Isn`t it great that we can get such good knowledge from the "Cub-Guru`s" on this board. Sometimes it is even free. :P

Thu May 13, 2004 11:52 am

I've used those so called carb kits from "others". There is absolutely no substitute for the Case/IH Kits. I wouldn"t use the "others" even in a pinch :!: :!: