Engine alarm - its always something...

[Monroe Boater]

Ever notice with boats that they tend to act up at the wrong time?We have been enjoying the beautiful weather on the lake this holiday weekend. For some reason, an engine alarm has decided to sound. Now I get to play detective. At least I am lucky, the 5.7's are carbed so it can only be temp, drive oil, or oil pressure. Already ruled out the drive oil reservoirs, tomorrow I will try unplugging the temp alarm sensors, and last the oil pressure alarm. I am thinking that the real culprit is a chaffed wire or bad connection somewhere. The engines had the manifolds replaced last year and run at 170 all day. Oil pressure has never dropped according to the gauges.
Any guesses as to what is tripping the alarm? It is the constant one.

 

[comsnark]

For these boats. . . all three alarms are constant, aren't they? When you turn the ignition key, you are "getting" the oil pressure alarm until the oil pump comes alive, right?

There are two temp sensors on each engine. . .one for the gauge, and one for the alarm. If your temps are fine, and you have a temperature alarm. . . the sensor is wonky. If the temps are wonky and you have a temperature alarm. . . .the engines are wonky!! First step would be to swap the sensors. (actually, the first step for my mechanic was to replace the thermostat -> which considering the cost of the thermostat was not unreasonable). If you have any doubts, shoot the engine temps with an IR gun -> it's a very good diagnostic tool for temperature problems.

Oil pressure would scare me -> I suppose you already checked oil levels for both engines? And if memory serves, there are two oil pressure sensors (one for gauge, one for alarm) as well.

Good luck!