2004 Mercruiser 4.3 intermittent alarm

[jjnorton]

I have a 2004 mercruiser 4.3 carb engine with an intermittent alarm (sounds like Morse code). I have changed water pump impeller, new thermostat, and new water temp sensor. With sensor wire plugged in I have an intermittent alarm when under power. Unplug wire to sensor and it stops. Is this a wiring issue? It is not a constant alarm - short beeps with no consistency. At idle no alarm but the beeps start with increase rpms on water. Will not do this off water with muffs. Changed all this out trying to solve problem without any luck. Temp is below 180 when running. Any ideas??? Seems like I am chasing a ghost.

 

[alldodge]

I have a 2004 mercruiser 4.3 carb engine with an intermittent alarm (sounds like Morse code). I have changed water pump impeller, new thermostat, and new water temp sensor. With sensor wire plugged in I have an intermittent alarm when under power. Unplug wire to sensor and it stops. Is this a wiring issue? It is not a constant alarm - short beeps with no consistency. At idle no alarm but the beeps start with increase rpms on water. Will not do this off water with muffs. Changed all this out trying to solve problem without any luck. Temp is below 180 when running. Any ideas??? Seems like I am chasing a ghost.

:welcome: to iboats

Could use a serial number to determine which sensors you have

 

[jjnorton]

Ser # OM685189

 

[jjnorton]

Please correct me if I am wrong but I think it has 3 sensors: drive lube bottle, oil pressure and water temp. I have unplugged the drive lube and the beeps remain. Unplugged the water temp sensor and it stopped. That's why I changed the water temp sensor.

 

[alldodge]

Please correct me if I am wrong but I think it has 3 sensors: drive lube bottle, oil pressure and water temp. I have unplugged the drive lube and the beeps remain. Unplugged the water temp sensor and it stopped. That's why I changed the water temp sensor.

Agree it appears you have only the three you mentioned, the issue comes from you previous post

It is not a constant alarm - short beeps with no consistency

Don't see how your sensors have an inconsistent alarm, even if one is going bad

 

[jjnorton]

Agree. It is not a constant alarm only short beeps at different intervals. When I back off the throddle it usually stops. I will check temp tomorrow with ir thermometer and compare reading to the gauge. Almost sounds like a short but I can't find a break in the wiring to the temp sensor.

Welcome any and all help. Took it to boat repair shop locally without resolution.

 

[Fun Times]

Is there a certain RPM, Speed the horn sounds? Rough water?

With the engine running, be sure to shake and wiggle all the wires you can to see if the horn will sound including power and ground wires/battery cables and the main power canon plug.

Bad/loose 12v power connections have been know to sound the horn on carbureted engine models. Did you unplug the temp sending unit plug that contains a yellow wire? The yellow goes into the ignition control module.

 

[jjnorton]

I did unplug the the yellow and black wire. This stops the intermittent beeps. When I replaced the sensor and thermostat I used oem parts.

Is there something else I need to check in regards to the yellow wire?

No set rpms. On land with muffs no beeps even with an increase in rpms. Put it on the water and once the boat gets on plane the beeps start but they are inconsistent

 

[jjnorton]

Ran the boat and temp is consistent with temp gauge - 159 to 170. Beeps start around 1500 rps but there is no rhyme or consistency with a certain rpm vs alarm

 

[Fun Times]

How did you install the sensor? Dry, Teflon tape or the red sealant that comes on the OEM sensor? Was the sensor OEM or aftermarket? Have a link or part number to it?

Have you recently replaced the thermostat housing gasket between the intake manifold and T/housing? If so, was the gasket OEM or aftermarket? And did you add sealant or go on dry?

 

[jjnorton]

The sensor was OEM and only had the red sealant that comes on it. Thermostat housing gasket was also OEM and made sure not to cover the rivets but used Permatex aircraft grade sealant / form a gasket. The beeps were as described before changing the thermostat, gasket and sleeve. Thought the sensor and / or thermostat could possibly be the problem. Beeps continued but at least I have a new thermostat and sensor.

I checked the yellow wire from the sensor to the ICM as Fun Times suggested.

I unplugged it at the ICM and found a kink in the yellow wire. I straightened it and re-taped along with the other wires as it leads to the plug for the ICM. After doing this, the beeps have stopped. Not sure if it was the kink in wire or a bad connection that was fixed by unplugging and then re-plugging it back into the ICM.

THANKS!!! Fun Times for helping me with this. Ran the boat yesterday after doing the aforementioned and did not get the first intermittent beep. Not sure what fixed it and hope it does not come back (knock on wood). Thanks again for guiding me in what seems to have been the right direction. :joyous:

 

[Fun Times]

You're welcome jjnorton I sure hope it turns out to be the problem.

Lately there have been a few similar type topics where members with later model carbureted engines have been sounding the warning horn for no apparent reason like yours and I don't believe there's been a cure for them. Wondering if they should be inspecting/cleaning the connector going into the ICM.

Also now that you mention removing/reconnecting the ICM connector and the warning horn seemed to have stopped thus far sounds sort of familiar. Pretty sure one other past member a few years ago did the same as you with success. Plus the temperature yellow wire going into the ICM is the only other thing/place the warning horn system goes into that's not related to the oil pressure or drive lube reservoir and it's always been a suspicion of mine of being an issue for many unresolved forum posts.

Using the new someone mentioned you in a post feature, I'm going to try and invite a few past members to have look at your post here to see if it may help them as well. It's worth a shot anyways.:noidea:

Wild0409 http://forums.iboats.com/forum/engin...-alpha-1-drive

nickmo http://forums.iboats.com/forum/engin...rcruiser-alarm

Four Winns Fanatic http://forums.iboats.com/forum/boat-...ttery-terminal

ralphy670 http://forums.iboats.com/forum/engin...rmittent-alarm

Good luck guys.

 

[nickmo]

Thanks for the invite Fun Times. I'm still having alarm issues. I will check the connection at the ICM. Is that the module that sits on the port riser?

 

[alldodge]

It still sounds like a water pressure sensor alarm so you may have some clogging/restriction in the line coming from the drive or in the water pickup area of the drive. Are you in salt or fresh water?

 

[Fun Times]

Thanks for the invite Fun Times. I'm still having alarm issues. I will check the connection at the ICM. Is that the module that sits on the port riser?

No problem nickmo!
Yes the ignition control module is typically found on the portside exhaust riser....Item number 7, http://www.mercruiserparts.com/Show...nbr=11741&bnbr=40&bdesc=Electrical+Components