90 Merc 115 alarm question

[narmer2000]

Is the oil alarm steady or beep? Engine pumps water and tank is full of oil but alarm goes off steady, shut motor off and turn key to on, alarm still goes. Start engine and it goes away. Thinking an oil sending unit may be malfunctioning?

 

[Dave1027]

Re: 90 Merc 115 alarm question

My book says a steady alarm is the overheat signal. When the oil tank has less than one quart left the alarm should be an intermittent beeping.

If the motor is cold and the oil tank has more than a quart in it then I'd say you have a sensor or module malfunction. Disconnect a wire to the overheat/temp sensor. If the alarm still sounds then it's the module that's probably bad. Also, if any wire in the system except the ground wire (blk) is shorted to ground the alarm will be stuck on.

I had a module go bad on mine. I replaced it only to have the new one go out shortly after.

 

[narmer2000]

Re: 90 Merc 115 alarm question

Thanks for the tip. I'll try that this weekend.