1997 mercury mariner 40HP 2 stroke over heat alarm

[duane haugen]

I bought this motor and am new to boating, but am mechanically inclined. took the boat out and had a constant alarm, irratic flow from tattle tail. change out the water pump, put muffs on ran in yard, still have alarm. HELP

 

[Jake_MN]

Re: 1997 mercury mariner 40HP 2 stroke over heat alarm

Does the alarm sound when the key is turned to the ON position or do you have to run the engine a while before it goes off?

 

[duane haugen]

Re: 1997 mercury mariner 40HP 2 stroke over heat alarm

Alarm beep twice when key was turned on, silence, then about 3-5 seconds later constant beep, motor not running, continues to beep constant (non-pulsing) with motor on.
I turned motor off and check continuity of temp sensor which from what I read is normally open, sensor checks out O.K. I also checked for pinched wires, or anything obviously shorted out and did not find anything, not sure what to check next. The alarm module does not show any discoloration, or pinched wires.

 

[Jake_MN]

Re: 1997 mercury mariner 40HP 2 stroke over heat alarm

So the alarm will sound even when the engine is not running and has not been run? If so, disconnect the tan/blue overheat sensor lead at the bullet connection. Turn on the key. If the horn still goes off with the engine not running, you probably have a faulty module. If the horn stops sounding, you probably have a faulty overheat sensor.

 

[duane haugen]

Re: 1997 mercury mariner 40HP 2 stroke over heat alarm

Changed out module today, all is well Thanks.

 

[olgoldtop]

Re: 1997 mercury mariner 40HP 2 stroke over heat alarm

I am having the same issue with my 40 hp merc, except my alarm is a beep beep beep and so on. its not a constant steady beep, and it will do it when just the key is on with it not running. i disconnected the barrel connection above the temp alarm and it still beeps when the key is in the on position. Would this still be a faulty alarm module?

 

[Derbyshire]

Re: 1997 mercury mariner 40HP 2 stroke over heat alarm

I am having the same issue with my 40 hp merc, except my alarm is a beep beep beep and so on. its not a constant steady beep, and it will do it when just the key is on with it not running. i disconnected the barrel connection above the temp alarm and it still beeps when the key is in the on position. Would this still be a faulty alarm module?

I have the same beep beep beep issue. Did you solve the issue? Please let me know.

 

[serico]

Re: 1997 mercury mariner 40HP 2 stroke over heat alarm

I have a '95 40 hp ELPTO, 2 stroke, 4 cyl, serial # 0G185067. Like the people above, I have an alarm that goes on erratically, even when the oil tank is full and the engine is not overheating. Can anyone tell me any of the following:
Where is the alarm module located?
Where is the temp sensor located?
What is that part number, and best place to buy, an alarm module?
A good outboard mechanic looked at the system, and said that the alarm module was the problem. I assumed that the temp sensor was located on the upper cylinder head, but unplugging it doesn't help.
Any help would be greatly appreciated.
SEO

 

[4tees]

Re: 1997 mercury mariner 40HP 2 stroke over heat alarm

Changed out module today, all is well Thanks.

So the alarm will sound even when the engine is not running and has not been run? If so, disconnect the tan/blue overheat sensor lead at the bullet connection. Turn on the key. If the horn still goes off with the engine not running, you probably have a faulty module. If the horn stops sounding, you probably have a faulty overheat sensor.[/QUOTE]

1993ish Mercury 40 hp 2 stroke 4 cylinder: constant beep alarm comes on immediately and stays on. IR thermometer shows under 100 degrees at idle, 140 tops at higher revs. Pulled out the tan/blue wire temp sensor wire at bullet connector and alarm still sounds off. Seems I have same issue as you had.
Where is the module you replaced?
Part-number?
Easy fix?

Thanks!!