Before I begin I need to say that I have searched the forums for this problem and have found a few similar occurences and suggestions to remedy the problem, but my problem has had a few more hours of investigation thrown at it thus far. Hence, my posting. Here goes.

I have a 20 hp Craftsman lawn tractor (461707-0145-E3) that stalls. It started last season when I needed to operate the mower 1/2 choked for smooth operation. This year I began mowing and the tractor needed to be fully choked in order to run smoothly. During the third cut of the season the mower stalled after about 45 min. It did not start again. My small engine repair shop took the mower. He replaced the fuel filter, spark plug, changed the oil and installed a carb overhaul kit. I finally got the mower back and began to cut with it and, guess what, it stalled after 30 min. I called the repair shop and he came out to take a look. The only way to get the mower to run was to disassemble the carb and start the engine. BTW, it's not a plugged gas cap - we tried operating with the gas cap nearly off. Gas came out of the carb and after re-assembling the mower ran fine for 45 min. He said that perhaps something was plugged and that cleared it out.

A couple days later it was time to mow. I started the mower up and began mowing. You guessed it: 35 min later it started to stall out. I was able to finish mowing with the engine fully choked. Every time I put a load on the engine (engage blades, let out quickly on clutch/brake, go up steep hill in 6th gear, etc) it nearly stalls out.

The repair guy is going to come out again to take another look. I've agreed to drain the gas (in case it's bad) to see if that makes a difference.

Any thoughts?