Quirky Alarm Yanmar 3QM

[Jerry A]

My Yanmar 3QM starts immediately and after running for about 2-3 minutes, one of the alarms goes off. Neither the Oil Pressure light nor the Overheating light go off. After about a minute of the alarm, it goes off and does not come back on. This happens each and every time I start the engine.

I have had a couple of suggestions, one possibly being a malfunctioning switch for either the oil pressure or coolant alarm and one possibly being air in the cooling system. Before I embark on replacing switches, etc., I wondered if anyone has experienced anything similar and can suggest what it might be. If it is an air lock in the cooling system, can anyone tell me how to bleed the system. I am aware of bleeding the fuel system but have not bled the cooling system before.

All suggestions are welcome.

 

[navigator97]

You might first check that all of the alarm LIGHT BULBS work.

 

[Ed Schenck]

Can you disable one sensor at a time? If the 3QM is like my old 2QM then it is just a spade connector that slips off. Having a hard time with the idea of an air lock since I assume you are raw water cooled.

 

[sailaway78]

Try the connectors

Check the connectors in the harness between the panel and the engine. I have had a problem with these coming partially loose. I solved the problem with mine by making sure they were plugged in good and solid, then taping them in a figure 8, to hold the two halves tight. It's pretty easy to check each on individually. Simply unplug the wire at the sensor, and ground it. With the switch on, this should both light the warning light, and set off the buzzer.

 

[zeehag]

my kat used to unplug nice n easy's alarms when we were in the gulf---- they are way easy to undo. good luck smooth sailing.