alarm sometimes sounds

[leroy 1988]

been awile but now I'm back:<br /><br />150 hp, 1988 merc. oil injected, both oil tanks full and caps tight. some time the oil alarm goes off at all speeds yet i no oil is being injected into engine, motor runs great, any idea where to start,,,<br /><br />Thanks guys you were a great help last time i was here...............

 

[ODDD1]

Re: alarm sometimes sounds

leroy, here is what makes the alarm go off:<br /> low oil in the engine mounted tank, you covered that.<br /> the motion sensor on the oil pump drive...if the gear is failing, alarm will go off, not an intermittent problem, it will progressively get worse.<br /> the oil alarm control box compares rotation of the oil pump shaft to one of the ignition coil outputs [usually #4] you know, one pulse on the sensor to one pulse from an ignition coil, if they dont agree, alarm goes off....now, if you have a bad switch box and #4 if misfiring, alarm still goes off even if oil pump is working.<br /> a bad oil alarm control box can fire the alarm any time it wants to....have seen many do just that on your vintage engine....