Carb Problems

[tparslow]

My 1947 Farmall Cub is having problems with the carburetor. Last year when it was running, it would run rough and hard to start. Easy fix clean and install a carburetor kit. Right, wrong. After 2 cleanings and 3 carb kits, 2 were low priced, 1 from IH was very expensive. No luck. When it is turning over it appears to be firing but does not take off. After several carburetor adjustments. i am wondering if my problem is something else. One thought is timing. What might others think?

[Bill V in Md]

I would make sure you are getting gas flow to the carburetor and that the float is set correctly. After that, I would check the ignition points. Depending on their condition you can either clean them with a points file and reset the gap or just replace them if they look worn (pitted or burnt). After that, I would check the ignition timing.

[Eugene]

Suggest complete engine tune up: starting with compression tests, then ignition system, lastly carburetor/fuel.

[tparslow]

Points are a good place to start. I'll give that a try. Thanks.

[staninlowerAL]

1947 would have originally been a magneto ignition but someone could have replaced it with a battery ignition. IH offered this as an upgrade conversion probably in the early 1950's. Just make sure what you are working with as the process is quite different for the two systems. You can download the electrical equipment service manual GSS 1012 at the Quick Links tab, top left corner of this page. It contains all you need to know about both systems. JMHO

[Eugene]

Points are a good place to start. I'll give that a try. Thanks.

My 1947 Farmall Cub.

1947 Cub. 75 year old tractor. Better check the motor's mechanical condition first. Or not, your choice.

[inairam]

IF you do the tune up I have had a number of issues with ignition parts even oem parts. I started using NAPA ignition parts and have been seen an improvement in reliability in the ignition area.

Distributor Cap Part # ECH IH350
Distributor Condenser Part # ECH IH200
Contact Set (Points) - Magneto - Ag Part # ECH CS1600
Distributor Rotor Part # ECH IH300 ( battery ignition only not mag)

[CharlieK]

thanks ^^^^^^^^^^^^^^^^^^^^^^^^^^^

good to know

[Cubfriend]

When adjusting the points, the gap for a magneto is .013 and the gap for a distributor is .020

[Cubfriend]

Points are a good place to start. I'll give that a try. Thanks.

My 1947 Farmall Cub.

1947 Cub. 75 year old tractor. Better check the motor's mechanical condition first. Or not, your choice.

As Eugene said, the “mechanical part of the engine” could be something as simple as adjusting the valves to help improve compression if they are set too tight from wear over the years.

[NJ Farmer]

Make sure you have the right parts in the right carb…….there are different main jet and discharge nozzle jet sizes in the IH 3/4 carburetors not to mention the Zeninth model…. (IH part 251 234 R94 or IH part 364 579 r91). See manual GSS 1411 Rev no1

Wrong sizes will effect the performance of the carb…..however I am leaning more toward ignition issues….

NJ farmer