yes, oil pressure switch is near the oil filter, under the cylinder head cover. if the switch is bad, the genny will start and run, but shut down when you release the start switch. the oil pressure switch supplies a ground path for the run relay on the control board. the way to check it is to remove the wire from the switch and ground it to a good engine ground. if the engine stays running now, then you need to replace switch. The switch is a N.O. type switch, which means that the switch is "open" when engine not running, but "closes " on oil pressure above approx 7-8 psi. Onan p/n is 309-0322. u probably wont find a suitable replacement at auto parts store, as most automotive oil pressure switches are "N.C." or normally closed type switches
