need starting help PLEASE

Mon Jul 05, 2004 7:49 pm

We have a 1948 farmall cub

It quit running after a few minutes a few weeks ago and kept this habit up. So after asking the local mechanic we checked out the magneto. It seems fine. We have also done the following in the last few days.

1. clean plugs and regap
2. new spark plug wires
3. new distributor cap
4. adjust the point in the mag
5. taken off head and cleaned and checked valves
6. retime magneto
7. checked carb
8. checked ignition switch (with multimeter,it worked. although lately i have had a schock every now and then and you have to hold it in to shut off tractor.)

Any ideas? i really hate to have the thing sitting there.


Mon Jul 05, 2004 8:09 pm

Have you checked to see that the gas and gas tank are clean? Look into the tank and check for rust or gunk. Make sure the sediment bowl is clean. Run some gas into a glass container from the fuel line and hold it up to the light and see if there is anything in it.

What is it like when it dies? Is it sputtering for a few seconds, or is it more like the kill switch is hit and it is instant dead?

Also, you may want to try to bypass the kill switch, it sounds like it is on the brink. May be the problem. If you are getting shocks, it may be grounding itself out, or not have a good ground.

Check the spark at the spark plug to be sure it is big and blue.

Mon Jul 05, 2004 8:12 pm

A couple of things to check: Make sure that the new plug wires are solid core wires, not composite. Magnetos do not work well with the composite wires. Also, when the tractor dies, try to check the spark quality right away. If the mag coil is failing when it heats up, the spark will be poor or non-existant when hot but may look OK when cold. The condensor may be failing as well.
You may however, have answered your own question. The fact that you are getting shocked when shutting the tractor off indicates that the switch is failing. You can try disconnecting the kill wire from the switch to see if the problem goes away.


Mon Jul 05, 2004 8:16 pm

Gas is flowing through the fuel line. right now the hood is off so i had a temp gas tank set up. lately though we have just been using starter fluid in air intake of carb just to get a few hits and I can't get any I did try bypassing the switch. I might try it again

When it would die before i started working on it it would be whenever you advance the throttle. The plusgs are sparking liek they should.

Mon Jul 05, 2004 10:16 pm

it sounds like a good fuel supply, sounds like you have ignition.

Also be sure you have good seals around the manifold to block, carb to manifold, and the two carb halves. It is common for the carb top half to be warped preventing a good seal, as well as the area of the carb that bolts to the manifold will warp. If any of these areas are leaking air, the fuel will not be sucked into the engine properly.

oh, I see you did check the timing.

Tue Jul 13, 2004 9:42 pm

49 cub--having same no start condition as stated. Haven't checked carb body castings for warpage but know the gaskets are not in the best condition. Anyone have a IH part # for a rebuild kit, my local dealer is of no help at all.


Somerville, Tn

Tue Jul 13, 2004 9:51 pm

I believe it is IH 354454R92 for a IH carb

Wed Jul 14, 2004 8:02 am

You may have a good fuel supply to the carb, but maybe not through the carb. Will it run if you keep spraying starting fluid? If it will, then you have a fuel problem inside your carb.

If you have a timing light, hook it up and leave it connected while the engine is running. When the engine starts dying, watch the light and see what the spark is doing. That will at least point you toward or away from the ingition system and let you focus on the fuel.

Good luck,