Interceptor

No help in the tech section so I'll try here.

The engines in my Fountain have oil temp . sending units installed in the oil cooler loop. Late last season my oil temp. gage on one engine would erratically peg to a extremely high temp. and stay there or possibly lower. Nothing else implied high oil temp. Oil looked and smelled fine, no discoloration. Engines operated fine.
The wiring at the oil temp. gage is secure so I suspect a bad sending unit. Other than swapping or replacing is there a way to troubleshhot the sending unit ?
ed

Deltarat

If I am not mistaken, the sending unit sends a variable ground through resitance to the gauge. Try taking the wire and shorting it straight to ground but that will tell you nothing other than the gauge works though. Then maybe try it with a resistor in series and see if it gives you a temp reading that is stable instead of just pegging the gauge.

Just my .02 but I dont know if it will work or not.

Beak Boater

If its only one gauge acting up, check the ground on that gauge, Its a pain, but you could switch the wires to the other guage and see if the erratic reads continue. Not sure how you can check the sending unit.

US1 Fountain

iTrader: (1)

Put it in boiling water with a candy therm. and compare against the gauge. Might only help if the problem is all the time though. But easier to just swap them from side to side.

As Delta mentioned, ground it out 1st to check your gauge itself. Sure it's not grounding out somewhere, pinched wire?

Interceptor

Thanks guys. I'll be working on the boat tomorrow and hopefully one of your suggestions will resolve my problem.
ed