Engine overheat/buzzers etc etc

[gashead1974]

Im just picked up my new outfit Ring 20 with Merc 200efi (all around early nighties). When I turn the key to the run position I get the 3 bleeps as normal. But as soon as I start it I get the constant tone. I realise this is an overheat warning but would that start as soon as the engine is started or would it not start sounding when the engine had been run for a few minutes and is reaching the overheat stage? <br />Grateful for any help, and the impellor has just been replaced.

 

[Boatin Bob]

Re: Engine overheat/buzzers etc etc

Don't think the engine has had time to heat up yet so suspect a false alarm, either the sender has gone bad or the sending wire has been pinched/shorted to ground. See if you can find the temp sender on the block and disconnect the wire, if the alarm goes away then it's the sender, if it doesn't then you have to look further along the circuit for the problem.

 

[gashead1974]

Re: Engine overheat/buzzers etc etc

Hi Bob, Went and had another play about yesterday. And this is whats was happening. First time I turned the key to run - no bleeps, engines starts first time - 30seconds later overheat buzzers sounds (constant tone) - turned engine off - removed thermo sensor ( the one in the back righthand side of the block. Turn key to run and the overheat tone starts again even with the engine not running. SO I replaced that and turned my attention to the module. Basically the only way I can stop this tone is to disconnect one of the wires from the the module. In your opinon do you think that the modules knackerd?

 

[Boatin Bob]

Re: Engine overheat/buzzers etc etc

Sounds like it especially with the sensor removed or like I said possibly a pinched wire to ground can cause it.