Weird problem, Overheat buzzer comes on as soon as you turn the key.

[can-amsledder]

1992 40hp Force, at least I think it?s a 92. Force by Merc.
As soon as I turn the key, before the motor even turns over the overheat buzzer is wailing away!
The first thing I thought is, it can?t be that hot under the cover. I took the cowl off and that didn?t help (I really didn?t think so) I started the motor and ran it for a minute and it continued to sound. It is pumping water, it has a new impeller.
Any ideas???

 

[wickware]

Re: Weird problem, Overheat buzzer comes on as soon as you turn the key.

Suggestions:

1. Disconnect at the thermostat to determine it the wire might be ?grounded somewhere else?.

2. Check the thermostat connection with an ohmmeter or etc to see if it is going to ground.

3. If the thermostat is sending a ground, and it is not hot, I would think it's bad (test it).

Good Luck,
JOW

 

[can-amsledder]

Re: Weird problem, Overheat buzzer comes on as soon as you turn the key.

Thermostat? You mean the water temp sending unit?

Okay, if I disconnect the sending unit the buzzer stops? Must be the sending unit, right? Could anyone explain exactly how to test?

 

[wickware]

Re: Weird problem, Overheat buzzer comes on as soon as you turn the key.

Thanks! Thermoswitch vs Thernostat and mine is showing in the attachment at the orange wire (below the bottom plug and d/n know if all are there). It gives you a ground connection when it's above its rated temp. I would say it?s already testing bad if it is working as a ground w/o the rated heat applied to it. Otherwise, I would say heat it in water above the marked rated temp or to boiling temp and check the threads/body against the electrical connection with an ohmmeter for continuity/connecting.

JOW

 

[can-amsledder]

Re: Weird problem, Overheat buzzer comes on as soon as you turn the key.

Right! After looking around thermoswitch is the proper name. Thanks for the help. I?ll test it tomorrow, but I?m pretty sure that?s all it is! This boat has been sitting for a few years, it?s been one thing after another but we?re getting there! Again, thanks for the help.