Oliver 1800 C USX 32

I'm still helping a neighbor get his 1800 running and stay running, and we have narrowed the problem down to the carburetor (fuel). It is set well, runs great, for about 20-30 minutes. At this point, it will die. It is still getting good spark at the plugs, so that is eliminated. Vacuum checks at the manifold are good upon proper adjustment. I'm confident that the carburetor and ignition are set well and it runs like that. Fuel is getting to the lift pump. Fuel is getting from the lift pump to the carburetor. Fuel surges well from the lift pump to the carb.

However, I have no experience with a USX 32. My experience with TSX carbs would be that the needle valve was plugged.

I took the bottom screw under the carb out and get very little fuel out of the carb. I have done no further disassembly.

Can someone help with what is likely the problem with the carburetor and why it will seem to get fuel and run for 20-30 minutes, but then not run for more than a minute or two. The carb was rebuilt in the last 5 years or so at Denny's Carb shop (I advised the prior owner of this tractor to have it rebuilt then.) It didn't solve his similar problems with the tractor, but he didn't really follow up with me after the rebuild and then just sold it. The current owner bought it from the buyer between them.

Hope this makes some sense. Just looking for some ideas before I remove the carb and open it up.

Thanks

Have you checked for something floating around in the gas tank that could be plugging the outlet? Just a thought.

yes, cannot seem to find any restriction occurring between the tank and the carburetor.

Plugged fuel cap vent?

Good idea, but did it without the cap on. I had the same idea!

In the summer time like this those carbs will ice over inside, the problem seems to be the fuel tank is over the motor and it evaporates the alcohol in the gas. Try a can or two of heet next time it does it. The only way to remedy this, if this is your problem, is to put on a different carb, a Zenith, or put an aluminum heat shield under the fuel tank. Of course, if this is the problem, it was what was the problem with my 1850 gas, took me over 5 years to figure it out. Hot humid days were the worst. The only thing I can think of why the aluminum carb will do that is cause the heat from the motor gets repelled from the carb instead of heating it up like the cast would.

Sounds like a restriction between the inlet fitting of the carb and the needle valve.

Some carbs have a filter screen in the inlet fitting. Look for that first.

Could also be the float level set too high, binding float, sticking needle valve.

Go ahead and take the carb off, see what is happening. They are simple, field repairable.