Only runs when I choke it

[Hey Old Man!]

Recently rebuilt the carb on my farmall H including new fuel line and see thru filter. Tractor starts and runs but only if choke is 3/4 closed. Carb seems to be getting plenty of gas(based on see thru filter and removing main adjusting screw, gas poured out of bottom of carb). When I hit the "sweet spot" of about 3/4 closed it seems to run fine, but looks to be running rich based on the exhaust, no suprise with the choke almost closed. My question is, where do I begin to trouble shoot this? Could it be the intake gasket? Anything else I should check? Any help would be appreciated. Thanks.

 

[Bob]

I was "second on the scene" with one that acted just like that. The guy who "repaired" it had left out a jet. I don't remember the details but the thread could PROBABLY be found over on the IH Forum, dating back to the summer of 2008, IIRC.

I have some photos SOMEWHERE, as well. I'll look into it a little if I get the time and post back.

 

[Hey Old Man!]

Thanks for the reply. I think I replaced everything with the exception of the throttle shaft packing because the kit did not include the metal packing cap and I was afraid I would wreck the old one getting it out. I did tap down the existing cap to tighten the packing on the throttle shaft but come to think of it maybe I should chck that to make sure it isn"t sucking air around the throttle shaft. Another possibility I thought of was a pinhole leak in the intake manifold. I"ll need to check for that. if you find anything else, let me know. Thanks for your help.

 

[Patsdeere]

easiest way to check for air leaks is to take a little starter fluid and spray it around the manifold and carb and if the engine revs up then you found your leak.

 

[Hey Old Man!]

Thanks for the tip, I"ll try that before I remove the manifold.

 

[rustyfarmall]

(quoted from post at 06:41:20 05/24/10) Thanks for the reply. I think I replaced everything with the exception of the throttle shaft packing because the kit did not include the metal packing cap and I was afraid I would wreck the old one getting it out. I did tap down the existing cap to tighten the packing on the throttle shaft but come to think of it maybe I should chck that to make sure it isn"t sucking air around the throttle shaft. Another possibility I thought of was a pinhole leak in the intake manifold. I"ll need to check for that. if you find anything else, let me know. Thanks for your help.

There is no throttle shaft packing. If you are talking about the shutter shaft, there is a seal where it goes through the body, but that seal is to keep dirt from bypassing the air filter and entering the carburetor. That particular seal COULD be missing entirely and it would NOT effect how the engine runs one little bit. It would however, shorten the life of the engine.

 

[Hey Old Man!]

You"re right, I meant to say the shutter shaft packing and I agree, it wouldn"t make any difference. One thing I did not replace because I could not locate an existing part was the ball bearing included in the kit. I read the directions several times but could not figure out how or where it was supposed to go. I am correct in assuming that it is a detent of sorts for the shutter shaft? If so where does it get installed and how do I keep it in place? Thanks for all your help with this, what a great resource, only hope I can return the favor someday.

 

[Seth Boyer]

I had this same problem on the last carb I built. Problem was solved by disassembling and double checking everything was clean. I think I ended up finding a bit of the main jet packing had got loose.

I'd just suggest taking everything back apart and blow out everything with carb cleaner and air. Can't go wrong plus you'll get some more experiance with rebuilding the carb!!

 

[chuck41]

My suggestion would be to soak that carb o'nite
in a good carb cleaning solution. w/o that you are not getting the "lime" out of those ports.
Just had another one recently-cleaned, but not
soaked in cleaner,run with choke on. Chuck