Another Leaking Carb

Tue Apr 06, 2004 12:00 pm

A local fellow cubber came by work Saturday with his IH carb in hand looking for the answer to the continuous fuel flow out of his carb, after a new kit was installed. :? He did install the IH kit and replaced everything. After a few minutes, we determined that the float level was to blame. He referred to the instructions that came with the kit for proper float setting. He returned this morning to say that all was well and the carb was not leaking. :D About an hour later, he shows up saying the carb is now leaking fuel again. :evil: Anybody got any ideas :idea: :?:

Tue Apr 06, 2004 12:12 pm

If the carb wasn't leaking and then started again I would suspect dirty fuel. Maybe some debris caught in the valve.

Tue Apr 06, 2004 12:17 pm

1 more thing,

Check to make sure the float doesn't have a leak.

Tue Apr 06, 2004 12:35 pm

One last step... make sure the gaskets under the needle seat and and nozzle are sealing. These are a commonly overlooked source of leaks.


Tue Apr 06, 2004 1:03 pm


Donny's right, usually there's crap from the tank or fuel lines keeping the needle from seating. Here's a few other things to check:

Warped bowl castings? Stripped threads? Fuel in the float?

The float may be contacting the side of the fuel bowl. Check the clearances on both sides of the float AND the end that swings. I had one carburetor where the bowl casting was bent inward enough for it to catch the float and caused major flooding or starve for fuel. Also check if the float axle is binding.

The cage gasket and fuel discharge nozzle gaskets can leak, use a fuel resistant thread sealant and sparingly apply it with a toothpick. Don't use teflon tape!

Even at the factory spec, the float level may be too high. You must check the fuel level with clear tubing attached to the bowl drain. Some floats are heavier than others and heavy floats will flood at factory settings. Fuel level in the bowl should be 9/16 - 5/8 inch from the gasket as installed on the tractor.

Make sure the needle and cage were replaced as a set. Needles and cages are different. I use the needle and cage parts from the Kohler small engine carb kit - they work very well.

Lurker Carl

Tue Apr 06, 2004 3:38 pm

Thanks for all the replies...I will speak with my fellow cubber tonight on the phone and will give him this info. 8)

Wed Apr 07, 2004 11:54 am

Spoke with my friend last night and leaking threads on the cage are to blame :shock: :!: He was able to tighten the cage and seal the leak. He is going back to the tractor today and inspect for leaks.