Engine starts but quits when key released

Hook up your coil directly to the battery and see if it keeps running when the key is in the run position. If it runs This will eliminate a coil problem and then you can check if you are getting voltage in the run position. Mine was in the wiring. Bought a new wiring harness, hooked it up, and the problem was there. FInally traced where power should be running and found that when the new splice to the voltage regulator was spiced in they spiced the nwire on the coating rather than the wire. Fixed that and works great now.