1999 Mercury 30hp continuous alarm

[OIIIO]

My 1999 Merc 30hp electric start motor (30ELHO) sounds a continuous alarm as soon as I turn the key to start it. The alarm continues indefinitely - just a continuous tone. The motor starts and runs normally.

Another post - http://forums.iboats.com/showthread.php?t=178108 - points to faulty sensors. I pulled the temperature sensor out of the block and disconnected its tan wire - no change to the continuous alarm. I haven't checked the oil sensor yet.

The service tech recommends replacing the alarm horn itself ($40). The horn is a two-terminal, ordinary looking piezoelectric alarm. It seems to make a lot noise and its hard to believe it needs to be replaced.

Before tearing any more apart, I thought I'd ask for help. Does replacing the alarm horn make sense?

 

[Laddies]

Re: 1999 Mercury 30hp continuous alarm

A steady tone is heat-you have unpluged the tan sencor wire and it didn't stop, next unplug the tan blue at the terminal block where it joins the 2 tan wires, if the tone stops it's the oil module thats shorted and if it don't you have a short in the boat harness

 

[Texasmark]

Re: 1999 Mercury 30hp continuous alarm

The alarm obviously runs on 12v. The other terminal is ground but you aren't supposed to have ground unless the temp sensor shorts out.

So, with your wiring disconnected at the temp sensor as you said, go to the alarm and disconnect the ground wire to it. I think your ign switch feeds 12v to the alarm so it can be off. Quick test is to measure 12v terminal with sw on and off to be sure. Otherwise you need the sw on to complete the gnd ckt.

Measure resistance from the (disconnected ground wire from the switch -) to battery -, however you choose to do that.

If you have ANY resistance, go and find your short. If your engine has an electrical connector in/on the engine, that would be a good place to "divide and conquer".

Mark

 

[OIIIO]

SOLVED: 1999 Mercury 30hp continuous alarm

SOLVED: 1999 Mercury 30hp continuous alarm

Thanks Laddies and Texasmark.

We traced the ground to the oil level sensor switch. The float was stuck in the empty position, even though the reservoir was full. We pulled the oil sensor from the reservoir and disconnected its wires. The alarm stopped.

We tested the sensor with a magnet. The switched closed when close to the magnet and opened when we moved the magnet away - seemed normal.

We disconnected the oil tube and pulled the reservoir off the motor. We emptied the old oil and thoroughly cleaned the reservoir with hot water and dish soap. After drying the reservoir, we reattached it and refilled with fresh oil. The float seems to be working and the alarm is back to normal.

Thanks guys.

 

[Texasmark]

Re: 1999 Mercury 30hp continuous alarm

Great, but oil is intermittent. For some reason I assumed you had a constant horn.........you must have had a constant intermittent horn. Grin.

Mark