False Overheat Alarm? - '99 225

[<Roy>]

I was running my twin 225's about 4000 RPM when overheat alarm sounded on port engine. Engines never throttled down on their own. Telltale flow is good. Alarm even sounds on port engine when fully cooled, without starting engine.
Disconnected Water Temp Sensor, no change. Could the problem be bad thermo sensor? Any ideas?
I would look at cooling system if the alarm didn't sound when engine has cooled overnight and engine was not running.
Thanks

[<boats.net>]

It sounds like possible an oil alarm, If you have disconnected heat sensor's the alarm should go off. Look at engine oil tank, if oil level is at the lower line on tank it will signal low oil and you would have an oil transfer problem

[<Roy>]

Multi-Function indicator indicates temperature, not oil level. Could be, I guess...
When I disconnected the temp sensor on the starboard engine, the alarm did not sound for that engine. When I did the same for the port engine, the alarm continued. So, I sort of eliminated the water temp sensor.
Thanks for your reply. I'll be standing by...
Roy

[<Slick Trick>]

Recently had similar alarm problems on 200hp; found defective wiring causing low voltage to the CDI; replaced faulty wiring/connections in the harness and 10 pin connector to resolve problems. Now ok.... good luck !

[<Roy>]

Thanks for the reply Slick Trick.
Faulty wiring is probably going to be the toughest to run down, but sounds like a possible culprit.
Where was the faulty connection/wiring? Just looking for a place to start...
Thanks,
Roy

[SLICK TRICK]

The engine wiring harness(YAM 200, 1990)has slices/connection inside the "taped-up" wiring....Remove the tape and inspect the numerous slices/connectors; replace as necessary. Also I found an "OPEN" in the Yellow wire from the 10 pin connector to the CDI... that was the False alarm Culprit..... Good Luck !