1989 Mariner 75hp continuous alarm

[sudsy]

Hello, i have browsed around at previous topics on here but i still seem stumped, hopfully someone will be able to point me in the right direction...I have a 89 merc 75hp mariner on a center console boston whaler montauk. When i put the key in the ignition and turn to "on" the alarm starts, I am pretty sure this is normal? then once i start the engine the alarm turns off. After running the motor for about 10 -15 minutes the alarm starts up a loud continuous beeeeeeeeeeeeep and i loose my RPM guage completely. If i turn the ignition key slightly to the off position i can tweek it enough so that the alarm stops, however i still loose my RPM indicator. I recently had the lower leg serviced and the impellar and leg sensor was replaced. I have seen on here that continuous alarms indicate an overheat, i can rest my hand on the motor for more than 3 seconds and the water isnt overly warm.

Also, When i first start the motor, i can wiggle the key a bit and this will also start the loud continuous beep, The sound then begins to get very patchy and and not a sharp continous beep.


I have read on previous posts a similar case, The person found that it was a oil warning module. Is there any way i can test this?

If anyone has any help that would be great. I am pretty hands on with mechanical and electrical, i just need a starting point.

thanks,
kyle

 

[sudsy]

Re: 1989 Mariner 75hp continuous alarm

Yesterday i disconnected the two blue wires coming from the bottom of the oil reservoir. I did a continuity check on the float sensor, with the reservoir full, it reads infinite resistance. When the reservoir is empty and float sinks to the bottom resistance was minimal. I'm pretty sure that this would be normal as it acts like a switch open or closed.....I followed those two blue wires to a small black box that has about 5 wires into it. I am guessing that this is the oil warning module i have heard people on here talk about. Is there any more tests i can do to prove this is malfunctioning....

 

[sudsy]

Re: 1989 Mariner 75hp continuous alarm

i replaced the oil warning module after proving the temp sensor and low oil sensor are fine. No more annoying alarm.