'49 Cub only runs on full choke

Thu Feb 14, 2013 8:09 am

Greetings all!
I inherited a '49 Farmall Cub. I can crank it, but it will continue to run only in full choke. When I try to ease the choke off it quits every time. I worked with it for about an hour trying different things, but no luck. Please help me diagnose the problem and offer a fix. It has the turning plow on it (looks like a giant wok), and I really would like to turn over the garden right before a freezing night to kill the grubs in the soil before spring. I've used it many times, but dad always knew best how to fiddle with it.

thanks

Re: '49 Cub only runs on full choke

Thu Feb 14, 2013 9:23 am

Turn gas off and pull main jet brass nut on side of carburetor and clean with a piece of telephone wire (soft copper)

And welcome to the forum.

Image
Last edited by Mike in Louisiana on Thu Feb 14, 2013 9:29 am, edited 1 time in total.

Re: '49 Cub only runs on full choke

Thu Feb 14, 2013 9:26 am

Like Mike said, but also make sure your fuel is clean and the tank is free from deposits or rust. There should be a screen inside your sediment bowl, and another inside the inlet of your carburetor to help filter out junk but it doesn't get everything.

Re: '49 Cub only runs on full choke

Thu Feb 14, 2013 9:33 am

Here is a helpful video:

http://www.youtube.com/watch?v=96ufIsL7FOU

Also, when you remove the main jet, you should have a steady flow of fuel coming out, if not, work your way back to the sediment bowl and look for blockages.

Re: '49 Cub only runs on full choke

Thu Feb 14, 2013 10:10 am

Check the vent in the fuel cap for obstructions, also.

Re: '49 Cub only runs on full choke

Thu Feb 14, 2013 10:33 am

Do you have fuel build up in the carbs air intake? If every thing else checks out i would think air leak.

Re: '49 Cub only runs on full choke

Thu Feb 14, 2013 6:39 pm

Also could be the choke is working backwards. A while back I had that problem and what happened the arm on the choke rod into the carb had come loose and the choke plate flipped over. When I pulled the rod I was actually opening the choke instead of closing it.

Re: '49 Cub only runs on full choke

Thu Feb 14, 2013 8:08 pm

Do as Mike said, let some gas run through the carburetor for a few seconds , this will get some trash out if there is any in the bowl. That should solve, or at lest help the problem. Report back after you clean the jet and flush some gas through the carb.
Boss

Re: '49 Cub only runs on full choke

Fri Feb 15, 2013 9:25 pm

Excellent! Thanks much to all! I will try these suggestions as soon as I can. The glass bowl does indeed have some sediment in it which, and some debris may have worked itself down to the carb.

I look forward to getting it running because the soil turning over by the disk turning plow is a beautiful sight to me. I'll try to make a video clip if I can do that and work the gears and hydraulic lift and steer all at the same time. I much admire that old tractor - made in America when things (and people) were solid and simple and made to last a lifetime or more.