ok, so my friend dumped about 1/4 gallon of nitro R/C car fuel into the empty fuel tank of my old work tractor and ran it. the engine was just re-bult to the tune of $300 about a year ago. the engine starts and runs for a few seconds then it dies and can't be re-started. it had a yard cart full of gravel behind this tractor going up my driveway and it died (the engine was at 3/4 throttle and was not bogging at all) i had to tow it up the driveway with the broadmoor. It will now only start every once in a while, it sounds like it wants to start but won't. any sudjestions?