2008. 4.3 ltr. Carb. TKS Mercruiser intermittent warning beeps

[Larry Baloun]

At 3,000 to 3800 rpm I get intermittent alarm beeps. Oil pressure is good, fluids are full,temp is approx. 180. From this forum I have found the likely problem is lube level sensor, temp. sensor or water pressure sensor. I have disconnected thelube sensor and still get the alarms. Where do I find the connection to the temp. & water pressure sensors

 

[alldodge]

Howdy

Really need to know what your serial number is, year also helps.
Are you getting an intermittent single beep or 2 beeps every minute?

 

[Larry Baloun]

Engine serial# 1a312851, year is 2008. Beeps are single intermittent beeps

 

[Fun Times]

Hi, welcome to iboats !

The Engine temp warning horn sensor is found on the thermostat housing on the port side...You should see 2 wires coming out of the sensor (Yellow and Black). One of the 2 wires should be heading to the Ignition Control Module. See item # 6, http://www.mercruiserparts.com/bam/s...1494/13798/170

The Temp warning horn is ran through the ICM.....Next time you are out on the water (or before you go out if desired) and the horn sounds, try disconnecting the two connectors on the ICM for a minute and see if the horn stops sounding at speed. We've had a number of past forum members successfully fix their phantom warning horns with this trying this procedure....Some had to try disconnecting the connectors a few times but eventually it seemed to work for them too.

The other item that sounds the warning horn would be a defective engine oil pressure switch which would be item number 10 in the following link located down by the oil filter area. http://www.mercruiserparts.com/bam/s...31494/13798/40
^And we've had a few of these too!!

Of course all of this info is only if nothing is found to be actually wrong with the engine systems making the horn sound off.

Please keep us updated on your progress with this issue until repaired as I'm sort of in the process of collecting how many times the idea mentioned regarding the ICM seems to work. Thanks and good luck!!!

 

[Larry Baloun]

Thank you so much for your help Fun Times.
The warning goes away when I disconnect the engine temperature sensor and the temp gauge does not go above 180. I assume this means I need a new sensor ...the part #6 you have referenced. Is there somewhere I can get part replacement instructions?

 

[alldodge]

. Is there somewhere I can get part replacement instructions?

If your real quick (have the new one ready) unscrew the old one and screw in the new one. You would loose a bit of coolant

Being a closed system you need to drain some coolant down below the sensor. Then unscrew the old one and screw in the new one, then refill

 

[Larry Baloun]

...there is no coolant. Is it the same procedure with an open system or are they layed out differently?

 

[alldodge]

With an open cooling system just remove and replace. I was thinking you had closed cooling because your post of temp being 180 degrees. Your motor should be at 160 degrees so you either have a gauge/sender error or a restriction somewhere

 

[Larry Baloun]

How would you determine if there is a blockage?

 

[alldodge]

How would you determine if there is a blockage?

You start with back flushing everything. Can then put some clear hose inline to see if there is air entering. Can also remove hoses like going to each manifold and see how fast it will fill up a 5 gal bucket. As things progress and if nothing is found then remove the risers and check for corrosion.

 

[Larry Baloun]

Ok everything has made sense until now. Beep went away when I removed the temp sensor wire. I have replaced with new sensor rhen replaced wire and beep came back. Beeps periodically at 3000+ rpm temp gauge reads approx 170. ...now what???

 

[alldodge]

Beeps periodically at 3000+ rpm temp gauge reads approx 170. ...now what???

Think your gauge is wrong and you are overheating. Check with an IR temp gun

 

[Larry Baloun]

What is "IR" and where do you check

 

[alldodge]

Inferred temperature gun. Can measure the temp of the thermostat housing. Can find them at many places like harbor freight, walmat, hardware stores

https://www.amazon.com/Masione-Temp...coding=UTF8&psc=1&refRID=QJ6SES85HYTWD4PC41JZ

 

[Larry Baloun]

Should the thermostat housing read the same temp as what the heat gauge is reading?

 

[alldodge]

Yes it should, give or take a tad

 

[QBhoy]

Hi
My friend had a similar intermittent beep. Turned out it was the oil pressure sensor that was knocked partly loose when last changing filter (presumably). Just make sure it's the temp sensor for sure...I may be wrong but when we unplugged the sender unit wires from any of the sensors...the beeping stopped.

 

[Larry Baloun]

Well that is interesting...i will try pulling the oil pres lead, however the beeping stayed when I pulled the lower unit fluid level sensor lead

 

[achris]

Engine oil pressure and drive oil are completely different and are not interconnected in any way.

Chris.......

 

[QBhoy]

Engine oil pressure and drive oil are completely different and are not interconnected in any way.

Chris.......

Of course Chris, but when we had this problem, when the intermittent beeping was going on....if we pulled any sender wire from the dash gauges or from the temp sensor or oil pressure sensor....the beeping stopped. Strange, but true.