Annoying intermittent engine alarm.

[griff4]

For electrical wizards: We have a pair of 2 barrel 250 HP 350's and after about 3 years since new our starboard engine alarm is intermittent. Of course, everything is OK. I have disconnected the temp alarm switch (after replacing it, which changed nothing), disconnected the drive oil resivour alarm wire connections, and still get the intermittent alarm at acceleration, cruise, or deceleration. All gauges read fine. It's my opinion that a short occures somewhere in the oil pressure switch alarm wireing. This is the little switch near the distributor. Has anyone had a similar diagnosis? I am going to look at the wires now that the weather is a little cooler and it's more pleasant to work in the engine area. Thanks for any suggestions. As you may already know, this system has only 3 items that trigger an alarm and there is no computer. Griff4

 

[perryk123]

The oil switches are notorious for getting some debris/moisture in there and not allowing oil press to register. Oil switch is different than oil pressure sensor. The switch operates at very low psi, its either on or off, no in-between. Rare but you might also have a bad ground if you see some corrosion in the area.

In a different direction, Try swapping the alarm from the port engine. I had one that would only come on while the boat was underway and the bow was up. The manufacturer installed the buzzer hole side up. It was keeping the water/ moisture, and contacting when the water moved around in there. Drove us nuts, as this is quite a simple system

 

[griff4]

Thanks, Perry. I will be looking at that little alarm "buzzer" which is behind the gauges within the instrument cluster. You could be correct. Since this is intermittent and with no particular pattern of annoying beeps, I have suspected a connection or wire shorting, rather than an alarm switch. We sure appreciate your advice. Griff4