My B doesn't cut off anymore except running out of gas when I close the valve. The on off switch has never worked and I could choke it down with the throttle but not anymore. any hints or advice

Mark,
If your machine is equipped with a mag, it's probably the push/pull kill switch is inop. (or toggle if equipped) I have new mag push/pull kill switch kits in stock which mounts in the OEM ammeter box. Comes with new switch, wiring and connectors. E-mail me if ya need one....

mark, if the tractor has a magneto then there is a very small threaded terminal sticking straight out to the right by the throttle shaft. there should be a small wire on this terminal. if you take a wire and touch the terminal and then touch the tractor frame with the other end, the tractor will die. Just like a lawn mower with a mag type ignition. It is not uncommon for the mag to burn the contacts on the little toggle switch and it will either be permanently off or on. Follow the wire from the mag to the switch and make sure it is connected. make sure the switch is grounded to the tractor frame. If evrything is connected, then the switch is bad.
----if you have a distributor and a coil, then it is just the opposite. the switch disconnects one of the wires to the coil. lift a wire off the coil (small wire, not the plug wires) and the motor will stop.

Maybe start with either removing one wire from your switch or using a jumper and shorting to ground, depending on whether you have a coil and distributor or a magneto. This way you will know if it is the switch or a wiring problem.

I am a new owner of an Allis Chalmers.
I would like to purchase an owners manual but not sure which one. It is model B(1952) and the serial no. is B118262. If you could help or know of someone that can I would really appreciate it.
Thanks Bob

I'm sure you can go right to your nearest AGCO dealer and order an owner's manual. If you don't know who your dealer is, go to www.agcocorp.com and use their find dealer function.

Replace the switch that is not working.