alarm issue on dual outboards

[skidplate]

I have dual Mariner 200 offshore (1994) motors on a large Robalo. The boat sat up several years before I got it. I have everything working except the alarm system. Both motors of course have separate wiring harnesses with independent alarm modules mounted next to the ignition key. When I turn the key to the on position the alarm sounds but does not go off after a few seconds. The alarm is a solid beep as if for overheating but the engines both run cool. What would cause "both" motors to have the same problem with independent harnesses. What and how to test ?


Thanks in advance

 

[Texasmark]

Re: alarm issue on dual outboards

The alarm is powered by 12v via the ignition key and ground. Ground is supplied via the warning module. Either you have a shorted sensor, shorted wiring to the horn, or a bad module. Ground should only be present when a problem exists.

Pulling wires till it quits is how I'd troubleshoot it. The temp sensors are in the heads and one should be on a tan wire and the other tan/blue. They short out to the head (ground) when overtemp occurs.

Follow them to the module. From the module the purple wire (should) goes to the horn. The blue wire(s) are for oil alarm which beeps ,not a continuous tone.

We just had a problem like that on the son's 150 and it was a bad temp sensor switch (the tan one on the port side was bad).

Mark