IH504 problems

Basically, the tractor will start and run for a short while but once it gets nice and warm, it starts sputtering like it is running out of gas. Yesterday I had to pull the choke out to get it back to the shed. I drained and flushed the tank, replaced the fuel bowl assembly, and also pulled and rebuilt the carb (however, this was my first time doing carb work, so that is still suspect). This problem was starting to manifest itself before the carb was rebuilt and I was hoping that would solve the problem, but that didn't work. If the tractor sits for a time, it will run alright for a little while before having troubles again.

On a sidenote, I also went through the ignition system and afterwards, I re-timed the motor. New points, condenser, plugs, wires, and coil were installed. I replaced the factory 6V coil with external resistance with a 12V coil. What is interesting is the voltage across the coil is 12V with the key in the on position, engine off. Once the engine fires, it drops to 6 volts across the coil. I thought it would be a continuous 12V since I took out the external resistance. Am I missing something here?

Again, thanks for any input you might have. This problem has made mowing roadsides a frustrating endeavor this last couple of weeks.

Chad

The short version of this is that a slow fuel system will allow the carb to fill when tractor not running and then engine will run well until carb is drained. The fact that pulling your choke allows you to keep it running a little longer points you in the direction of fuel delivery not ignition.

Regards,
Sean

The machine can usually run for 6-8 minutes before sputtering out.

I'll check the fuel delivery system again. I did drain and flush the tank once and replaced the sediment bowl, screen, and assembly. Actually, there was no screen in the fuel bowl assembly. That wasn't what I wanted to see. I wonder if it pulled something large into the carb due to lack of a screen? There was some debris in the tank before I flushed it. I think I got most of it out but maybe I missed something. I should probably crack open the carb again. When I did flush the tank, I took the fuel line off at the carb and opened up the valve at the fuel bowl to drain all the fuel. Fuel came out quickly. However, this next time I think I'll also take K.B.'s advice and remove the screw at the bottom of the carb and see how much comes out and then drain the tank again.

Again, thanks to all for the responses. I really appreciate it.

Chad