troubleshooting a problem

[bwatson]

Here is the problem: My cub will crank and idle fine in the first three notches but when I advance the the lever on the steering column it kills the tractor. I can close the choke 1/2 - 3/4 and then I can advance the lever and rev the engine up. The fuel/mixture screw is pretty much all the way in. I am using a small clean auxillary gas tank with an inline filter

Is the problem in the Governer, the carb or somewhere I not thinking? Could it be a spark or timing issue?

This tractor has been sitting outside for years and I'm in the process of getting it running. I would appreciate any suggestions or things to check

[Oscar Meier]

I would inspect the main carb jet to make sure its not corroded up or dirty. Take the jet out of the carb and clean/soak it in carb cleaner. Reinstall the jet and see how she runs.

[Bigdog]

The problem is either not enough fuel, or too much air. Do as Oscar suggested, clean the main jet. If that doesn't help, start looking for a leak around the intake manifold / gaskets etc. Leaks can be detected by using an unlit propane torch aimed at the mating surfaces. If it smoothes out, you've found your leak. Use caution and keep the torch away from ignition sources.

[Lurker Carl]

Here's another a long distance guess - the float may be stuck.

Get a carb kit from IH Case and rebuild it. Anything that has been sitting unused needs a good cleaning and readjustment. Gunk left behind from evaporing gasoline and corrosion will create havoc inside the carburetor. Corrosion eats away at the aluminum castings leaving behind lots of particles that block the tiny orifaces within the carburetor.

The fuel mixture screw affects idle and low speed mixture only. Screwing it in for a rich the idle mix, screw it out for a leaner mixture.

In addition to what the others suggested, remove the inline filter. They tend to restrict fuel flow. If you haven't already, check the fuel line for obstructions or kinks.