HELP!! 1977 200 hp v6 alarm

[KCKracker]

So I'm at the water right now, I go to turn the key to start my main its a 1977 200hp v6 and the control box is buzzing loud. It's never done this and last start up two days ago all was tip too. I didn't even know it had an alarm.

What will set this alarm off being a 1977?

 

[Masteraustin]

Re: HELP!! 1977 200 hp v6 alarm

So I'm at the water right now, I go to turn the key to start my main its a 1977 200hp v6 and the control box is buzzing loud. It's never done this and last start up two days ago all was tip too. I didn't even know it had an alarm.

What will set this alarm off being a 1977?

Usually the standard buzzer is for over temp. On our 97 Trophy it shorted out due to corrosion of the wire and it did the same thing even when the engine was cold.

Just a thought.

 

[MaPaHa]

Re: HELP!! 1977 200 hp v6 alarm

You should have a temp sensor on each head. They short to ground when the motor over heats and that sounds the alarm. You can test the alarm circuit by moving the insulation back on the in-line connectors and shorting each one to ground and the alarm should sound. If you get a constant alarm you can disconnect each one and the alarm should quit. If the engine is cold and you get an alarm and you figure out which one it is, it's probably a bad sensor. If it happens when the motor gets warmed up it could be a overheating motor. If you have any kind of temperature probe, check the water temp or cylinder temp. My 140 runs between 125-145 degrees.

 

[emdsapmgr]

Re: HELP!! 1977 200 hp v6 alarm

The horn is for an overheat. It should come on once either head heats up to at least 212 degrees. The hot horn will silence once the head cools to 175 (still too hot.) Since the engine may be cold, it's unlikely it's overheating. Probably a wiring problem. MaPaHa makes a good comment to check for a shorted overheat sensor in one of the two heads. Could be an exposed/shorted wire in the control box, a bad head sensor, or even grounded wire in the harness.