How can I test that my overheat alarm works (2005 Yamaha 40hp 4-stroke)

[taymag]

I am about to buy a boat, want to make sure the overheat alarm works, I know you ground it out or something but forgot. I want to test directly from the alarm first, but should I also get a beep on the key turn that will indicate overheat alarm works or is the key turn beep a different alarm check?

 

[ClassicAQ]

Test the switch's continuity by placing in hot water, attach pig tails to multimeter. Discontinuity below 183º, continuity above. Test alarm circuit by unplugging engine side pigtails from switch, then plug engine side pigtails together to complete signal. Turn key ON. Alarm should sound.

 

[JinsooKim]

I am about to buy a boat, want to make sure the overheat alarm works, I know you ground it out or something but forgot. I want to test directly from the alarm first, but should I also get a beep on the key turn that will indicate overheat alarm works or is the key turn beep a different alarm check?

just remove over heat sensor.

and boiling water.

get the sensor into boiling water.

aftet that, check continuty by multimeter.