M stall's when engine get's warm.?

Hello all,
I have a Farmall M that starts good but after it runs for a while maybe 5 min., the engine wants to stall. When the RPM starts to drop I will pull on the choke for just a second then open the choke. This only works a couple of times, then the engine won,t stay running. I have rebuilt the carb with no change. I have sprayed carb cleaner around the intake manifold gasket with no change in the RPM. Any ideas on what could be causing this?
Thank you!

There may be a screen behind that tube fitting on the carb where the gas line connects that may be plugged with rust or dirt. Make sure there's full stream of gas from the gas line hold a clean container & catch the gas.

Have you chesk for fire to your plugs ASAP when the engine dies? Could be a weak coil when it gets warm. Hal

Hi Harley
just had the very same problem on my A we changed the head gasket no change then we changed the coil still no change then the
condenser STILL no change by this time we were getting desperate my neighbor contacted a old tractor mechanic and he informed us the problem IS in the carb we took the carb apart and he informed us that theres a brass pickup tube in there and it has to be removed and theres some real tiny holes that have to be cleaned out
we did this this and now it runs great im assuming that this is a marvel carb i hope this helps

Check the fuel flow to the carb., by disconnecting the line at the carb and drain out at least a quart or more. Is the fuel flow a steady stream or does it start to slow down? It could be the vent in the gas cap. The screen in the sediment bowl could be partially blocked. Can you drain the gas out of your tank and then remove the entire sediment bowl assembly from the tank. Mine was partially plugged and would not allow enough gas through it. Do you have an inline filter? Some cause a problem. Remove it. The inlet to the carb may have a brass screen in it. It should be attached to the fuel line, but maybe it broke off and it is stuck in the carb an it could be plugged.
SDE

Is your gas cap plugged thereby creating a vacuum in the tank when running the engine?

At first blush, this sounds like a fuel flow problem. When the carb bowl is full, the tractor will run until the bowl is empty. Also, by putting on the choke, it will draw a bit of fuel faster than the gravity flow systme will deliver.

Previous points have called out things to check singly, so I will put them all in one place: check fuel bowl intake that sticks up in the tank to make sure there are not flakes of rust or other sediment blocking it (i have had this problem, and it took me a long time to discover). Then make sure you have good flow through the bowl itself, as there is a screen inside the top of the bowl. Next check the line itself to make sure it is clear. Next item is to check the inlet screen in the carb, which is inside the top of the carb where the gas line threads into. Lastly, check all ports and passages in the carb. Also, try all of this with the gas cap off.

If all of these things check out, then I am stumped. One last note, an engine that runs for a short while then quits can also be related to a bad coil, as it quits after the coil heats up. However, you state that pulling the choke out for short periods will keep it running, so that would not make a difference on a bad coil.

Let us know how this turns out......

Hello all,
Thanks for all the great suggestion"s. I will give them a try.

Thanks again!

One other thing to check. When you had the float out, did it get bent? I was having the same issue, after I found what seems like 5 pounds of leaves and debirs in the tank. Got all that cleaned out, if worked better, but still wanted to stall and run lean, then I took carb apart again, and found side one of the float got bent a little and was hitting on the side of the carb....and would not let the float move freely, henceforth, the needle would not open. The way to check that is to take the drain plug out of the bottom of carb, see if you have a steady flow coming out of there, let a couple quarts drain out. If you do not have a steady flow, then you have an obstruction in the fuel supply system, if you have good flow, then you have something in the high speed jet in the carb.
Jim