I warmed up my 953 (s/n 20z) today and used it about 10 minutes and shut it off for about an hour. When I fired it back up the engine oil pressure warning light and buzzer went off, no gauge only warning lights. I checked a few things and started it again, same deal. So I went and got a mechanical oil pressure gauge. I hooked it into where the FSM says to check pressure. I started it up and had 45 psi hot at low idle. High idle hot was about 70-75 psi. I left the gauge hooked up and ran it all afternoon, keeping an eye on the gage, no problems. To me this means that the problem is in the warning system. Has anyone experienced this? Any tips on how to start running this down?
check the sending unit on the block... i've had them fail from time to time
The oil pressure switch is behind the air filter housing on the head. There are two of them on a tee. One is for the idiot light and the other is for the hour meter. Both are the same part so you can swap the wires or test the switch. It should be open with the engine not running and closed with it running. I think the one on the side is for the hour meter and the one pointing forward is the oil pressure.
Isn;t one for the excitation of the alternator? I maybe mistaken tho.
Turned out to be a bad crimp connection on terminal that hooks to sending unit. New terminal = problem solved