Engine alarm buzzer always on

[saillavie38]

I have a 3QM30 which recently began to show some strange behaviors.

Engine not running & key on seems normal: the oil and charge lights are on, and buzzer sounds. The alarm actually has two sounds... the buzzer, and a high pitched tone. In the past, starting the engine both lights were extinguished and the buzzer and tone stop.

This past weekend though, once the engine starts, both lights go out, and the high pitched tone stops, but the buzzer continues. The engine seems to run fine in all other respects. I'm assuming that with the lights going out, the oil pressure and charging are OK.

I'm not famiar with the inner workings of the alarm, but is it possible that one of the internal diodes might have failed and caused the alarm to sound continuously? What else might be going on?

Larry

[denby]

check the electrical connections, you might have a bad connection or it might be a diode. Either way the alarm is not getting the signal or it is stuck.

Dennis

[sailingdog]

Have you checked the oil pressure and level and the alternator output voltage??

[Goodnewsboy]

My Yanmar has an overtemp alarm that goes off if the cooling system is not full. It is controlled by a thermal switch. Check your manual. Make sure the system is topped up.

[Rockter]

Make sure... sure.... sure.... the oil pressure is correct before dismissing the alarm.

[billangiep]

On my Yanmar instument panel there is a three way toggle switch, down is off, center turns the tahco light on and up is the test for the high temp alarm (engine running).
Bill,