I guess it could be the rust in the gas tank, but that sure seems odd.
The truck always start when the motor is cool. I run it for 10 minutes and the idle is fine, everything is fine. Then, it just randomly dies. If I check the carb at this point, it still shoots gas into the engine just fine. With gas in the motor, it should start up regardless of a little rust. I'm starting to think it must be the coil.
