Allis Chalmers WD 1951 S/N 105177 Eng# WD313842

ken devening · Sep 17, 2008

I need help. My tractor starts fine and runs for 20 to 30 min's and starts cutting out and will not take the load. I have to disengage the pto and baby it back to the shelter.
I have been working on it since Feb this year. If any one has a idea please let me know. I have tried ever thing and it still keeps doing the same thing.

Mike (WA) · Sep 17, 2008

Well, it sure sounds like a bad coil, but if you've tried everything, you've probably already replaced it.

El Toro · Sep 17, 2008

You need to check for gas flow to the carburetor.
Could have blockage in the tank, gas line or the carburetor could be dirty. There may be a screen behind the tube fitting where your gas line connects to the carburetor and it be full of rust or dirt. When it quits running you need to check for fire ASAP to the sparkplugs before the engine cools. Could be a weak coil too. If there's fire to the plugs its probably a fuel problem. Is there a fuel filter in your gas line?
It may be the problem. Hal

ken devening · Sep 17, 2008

Thanks El
I have replaced the coil and reworked the whole fule system tank and all. It is driving me nuts.
Nothing I do stops the problem.
ken

ken devening · Sep 17, 2008

Thanks Mike
Yes I replaced the coil and other things. Nothing stops the problem.
ken

school boy · Sep 17, 2008

you said you did the tank. Did you give it a total cleaning? If you just rinsed it out their could still be chucks of rust that move around and after a while plug the hole. I have put stand pipes about 1 inch in the connection of the sediment bowl to stop the chunks from gettingto the hole. Usually a small piece of copper tubing will just press in.
Good luck

ken devening · Sep 17, 2008

Yes I had the tank cleaned out with acid and it was cleand to the org. metal.
Thanks
ken

Dave in Tx · Sep 17, 2008

spark plugs are bad about that if you idle much.
also points gapped to close. try a hotter range plug.

Bob · Sep 17, 2008

Have you changed the condensor, as well as the coil? (Applies to battery ignition or mag.)

If "battery ignition", check to see if the voltage on the ignition switch side of the coil begins to drop at the time the "bucking" starts.

ken devening · Sep 17, 2008

Thanks Dave
I have tried changing the plugs. I will check the points and I do have a new set I could put in.
ken

ken devening · Sep 17, 2008

Bob
You said "bucking" that is exactly what its like. I am not good with the electric problems.How would you do this?
I have changed the condensor & coil. I have a friend that will help me with the electric.

KF · Sep 17, 2008

Does your fuel line run next to a hot manifold where vapor lock might occur? Or does your manifold or exhaust have a crack where hot exhaust is blowing on the line. Also, if you have a flow problem from the tank it should show up at the sediment bowl first. Look at in when the engine cuts out. Also, look at your float in the carburetor to see if it is free and not sticking in the up position. A lot of those carburetors have a little screen on the inlet of the carburetor. It may be dirty.

El Toro · Sep 17, 2008

Replace the condenser. Hal

El Toro · Sep 17, 2008

Have you checked to see if there's fire to the plugs when it quits? Is this a distributor or magneto? If its a distributor and there's no fire when it quits. Run another wire from the battery to the coil and see if it runs ok. Hal
PS: May be the switch.

Bob · Sep 17, 2008

Have your electrical guru friend monitor the voltage coming out of the ignition switch to feed the coil to see if the voltage drops due to a bad ignition switch or other electrical problem.

Also, you can put an "in-line spark checker" on one of the spark plugs, and watch to see if the spark gets weak or erratic when it begins to act up.

If the spark remains OK, that pretty much rules out ignition problems, and you can concentrate on the fuel system.

El Toro · Sep 18, 2008

Check that valve clearance and set them at .013" Cold. Hal

Janicholson · Sep 18, 2008

Determining if it is fuel or spark is the main issue for further effort. As stated below, your positive efforts are one notch short of a fix. Not mentioned below is the possible plugging of the vent in the gas cap. If plugged, it will act just like that.
Erratic poor spark is still spark. Measure the maximum spark jump when cold, then check it when it is failing.
New bad condensers are often in the box from the dealer, change it one more time. JimN

ken devening · Sep 18, 2008

Checked the gas cap.
Will check the the spark jump.
I have changed the condenser 3 times.
Thanks for your help.
Ken

ken devening · Sep 18, 2008

I did this.
Thanks for your reply.
Ken

ken devening · Oct 7, 2008

Thanks to all of you for helping. The problem was the Rotor in the distributor. The key on the inside of the rotor was chipped and would work is way up and become loose which would cause it to cut out.

Ken

Allis Chalmers WD 1951 S/N 105177 Eng# WD313842

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