False Audible Alarm

[BobMaio]

I have a 2000 Sea Ray with a 2007 4.3 Merc I/O. Recently the audible alarm would randomly come on while cruising. Just for a few seconds then go off.
Gear oil level is fine, oil pressure is fine and water temperature is all to specs. Sounds like a false alarm signal to me but I don't know where to start to look for the culprit. Can someone please give me some direction on how to fix.

 

[achris]

Re: False Audible Alarm

Is this a MPI or a carburetored engine? When the alarm goes off, what is the tone? Is it like a beep every 2 minutes?

Chris...

 

[BobMaio]

Re: False Audible Alarm

Carbureted engine. NOt sure of the frequency of the beep but it is an elongated beep. It seems to come on periodically. I never thought to time it. I cruised for an hour with nothing, anchored the boat for 3 hours and on my return trip it started beeping in a periodic manner. It may have been every couple of minutes but it seemed more frequent. The last time I had the boat out it started right away and seemed more frequent then every few minutes. ON another note, the most recent trip the weather was cool and the trip before that was hot.

Any help will be appreciated.

 

[achris]

Re: False Audible Alarm

There are 3 sensors that go into the ignition control module (the module is what actually fires the alarm), oil pressure switch, engine coolant temperature switch and drive lube oil monitor oil bottle. I would disconnect each one of those in turn and see if the problem goes away (then you found the culprit). If it doesn't go away, disconnect all 3. Still there? the module may be the cause. The other thing I would check it for a chaffed wire in the harness that goes to the alarm module (it may be intermittently grounding), it's tan with a blue stripe...

Chris......

 

[BobMaio]

Re: False Audible Alarm

I understand what you are suggesting but I have to confirm something: 1) For oil pressure I disconnect the single lead on the sender to force an open-to-ground condition hence shutting off the alarm. 2) For temperature I disconnect the single temp sender lead which also provides an open-to-ground condition. 3) Disconnect both leads from the gear lube monitor which I think also provides an open-to-ground condition (not sure of this one). So if I have it correctly, by disconnecting each of these until I no longer hear the beep will pinpoint which sender is bad. If all 3 are disconnected, and the beep still happens, then the module is funky. Right?
On a related point, today I was trying to force the beep and could not. I was working on the boat in my yard hooked up to muffs. I thought if I shorted the connections to ground I would force the alarm to beep. I tried this to no avail. I could not get the alarm to simulate a problem situation. Am I competly off in my understanding of how this alarm system works?

 

[tank1949]

Re: False Audible Alarm

I have a similar set up and former owner cut wires going to buzzers. STUIPID. I am back tracking and checking it all out to get it up to factory specs. Make sure you pull switch wires and not sender wires for testing. You problem my be capicitor failing. There is a 15 or so second delay when testing mine. I suspect MC didn't want complaints from other boat owners because the alarsm can be loud and if they come on immediately, you would allways hear them when firing up motors. Anoying. Grounding leads to block and waiting 15 seconds, I have been able to test mone so far.

 

[achris]

Re: False Audible Alarm

No, your understanding is correct. Just be aware that there are 2 senders for oil pressure, one is the alarm switch, the other is the sender for the oil pressure gauge on your dash. Same with the temperature. Each of the alarm switch wires is tan with a blue stripe. If you disconnect all 3 wires and the alarm persists, then the module may be faulty, yes... However, grounding any of those wires SHOULD trigger an alarm condition, and sound the alarm.

The drive lube bottle has 2 black wires coming from the bottom, one is the alarm wire and will be connected to a tan/blue wire, the other goes to ground and will be black.. in terms of a working system it wouldn't matter which wire you disconnected, but if the fault is the switch in the bottle grounding (not really possible since the bottle is plastic), then I would always remove the tan/blue wire for testing purposes....

HTH,

Chris.....

 

[BobMaio]

Re: False Audible Alarm

Thanks for you help Chris. I was pulling the wrong lead off the sender. Now its just a matter of narrowing down the culprit.