Farmall Cub

I replaced the carburetor on my cub in '07 with a IH. It suddenly started leaking badly while parked. I've replaced with new seat and needle, gaskets, set the float, sure the float isn't sticking, read and read this forum about carbs and tips. The excess fuel is pouring out of the discharge nozzle, but it appears to be above the gasket and above the nut. My question: is it possible that the nozzle no longer fits tight enough within the nut and that could be the place of the leak? Thanks.

Arnold,

Please explain how you know the fuel is coming out of the discharge nozzle above the hex area.

The threads on the discharge nozzle are below the normal fuel level in the bowl. Adding a bit of Permatex #2 to both sides of that little round gasket should help seal that area. Be sure the discharge nozzle is not cracked from bending or attempts at straightening.

The discharge nozzle should be a one piece deal, machined from a single piece of brass. As Bus Driver mentioned, I've seen them leak at the gasket so seal that up and inspect it closely for cracks.

I pulled the air hose off the carburetor and looked in to see fuel pouring in. Visually I traced it to the discharge nozzle seeing it puddle above the hex area. Maybe it could be spilling out of the top and running down the nozzle. That's why I wondered if the nozzle and hex ever lost their their tight fitting. The nozzle machining looks like they were press fit into place, but if they are machined as one piece then that's not the culprit.

Check needle valve and seat and gasket for fuel leak.

Some place on this board is photos and a description of bench testing carburetors for leaks and fuel level.

Edit: Search "bench test carburetor" on this site. 11 hits.

Thanks, Arnold. I agree with Bus Driver's suggestion of adding a sealant to the discharge nozzle gasket. I would do the same thing with the needle seat gasket. Make sure you limit the sealant to the gasket, leaving all the orifices unobstructed. When you remove the carburetor, be sure to re-adjust the carb to governor linkage per the service manual. Let us know how you make out.

" Lurker Carl's Cub Carb Fixes" is not readable on my Mac with Firefox. Does anyone know of another way to read these tips, and service manuals?

Before gooping everything up with sealant, might want to find out for sure what causing the fuel leak. Fuel leak is the symptom, source of the problem to be determined.

Arnold wrote:" Lurker Carl's Cub Carb Fixes" is not readable on my Mac with Firefox. Does anyone know of another way to read these tips, and service manuals?

Arnold:

Firefox requires - IE View - Firefox Extension although there have been a number of iterations of Firefox since I linked to that. IE View 1.5.6 is the newest version and the server has been updated. This is another reason why I don't much like Firefox and prefer Opera.

The top of the discharge nozzle is higher than the normal fuel level in the bowl. So fuel is getting into the bowl after the needle and seat are supposed to stop the flow.
Not sure where the concept of "goopping" came into to play. For that gasket, I apply the sealer with a toothpick, let it dry overnight (at least) and then assemble. No problem with excess material.

Bus Driver wrote:For that gasket (discharge nozzle), I apply the sealer with a toothpick... and then assemble. No problem with excess material.

Same here. No "gooping".

Arnold wrote:The excess fuel is pouring out of the discharge nozzle, but it appears to be above the gasket and above the nut.

Bus Driver wrote:The top of the discharge nozzle is higher than the normal fuel level in the bowl. So fuel is getting into the bowl after the needle and seat are supposed to stop the flow.
Not sure where the concept of "goopping" came into to play. For that gasket, I apply the sealer with a toothpick, let it dry overnight (at least) and then assemble. No problem with excess material.

Concur Bus Driver, The fuel level in the carburetor bowl is suppose to be approximately 5/8" below the nozzle's highest elevation. The problem is some place in the needle valve, seat area, float setting, or crack in carburetor top.

Putting sealant on gaskets is not going to solve the problem.

Guys yawl need to get on the same page , Eugene they will leak around the threads if the gasket is not sealed, how ever I opt for a new gasket , not a sealer

If the gasket around the needle seat is not sealing completely, excess fuel will flow into the bowl while the engine is stopped.