Mercruiser Alarm
 

What's the best way to isolate a soft alarm going off on one of my 454 MPI motors(1999)? It only goes on for one second then off for three seconds and then just repeats itself in this sequence. Once I get over 2900 RPM the alarm goes silent. I am trying to isolate the problem while my motor is idling on the trailer right now. Is there a way to check each sensor using a ohms meter while it is just idling? I do know it could be high water temperature, low oil pressure or low gear lube. All three seem to be fine upon checking the gauges and the level in my gear lube monitor bottle. This is driving me nuts! I believe if any of these sensors show a resistance with an ohm meter it could be going bad but I am not absolutely sure this is the case.

I had some spare time this afternoon and was able to isolate the bad sensor. It was on the rear of my engine for the low oil pressure warning. I placed my ohm meter across the sensor and got a reading of 18 ohms. I checked my other engine and the was no continuity which indicates the other sensor is bad. The resistance showed up with the sensor wire disconnected. I will be placing an order for a new sensor on Tuesday.