Constant Alarm

[repair man]

50 mercury 3 cyl. 2-stroke OT045541: overheat alarm stays on and engine is cooling. Any thoughts or help please & thank you in advance

 

[repair man]

Re: Constant Alarm

I have disconnected the temp sensor and alarm stays on.

 

[Iceman66]

Re: Constant Alarm

Inside fault in oil warning module I guess, disconnect the black wire going from module to ground .
If alarm then stops, module fault. If alarm still sounds, the wire from sensor has contact with ground somewhere between sensor and remote control.

 

[md88]

Re: Constant Alarm

My 1995 75hp 3 cylinder did the same thing. It was the warning module bad. Warning module is for temperature and if your oil injected, oil level.

 

[repair man]

Re: Constant Alarm

My 1995 75hp 3 cylinder did the same thing. It was the warning module bad. Warning module is for temperature and if your oil injected, oil level.

Disconnected oil sensor in tank & alarm goes away !!!! Im not finding a warning module, but I will look !! Thanks

 

[carholme]

Re: Constant Alarm

Your s/n comes up as:

MERCURY - ( 50 H.P. (2000 ))
Serial No: 0T045541 Model No: 1050412WD

Parts and Service Bulletin list for s/n 0T045541:

Search Results - Crowley Marine

Service Manual is P/N: 90-852572 and if you would like a copy, drop me a PM with an email address.

Don't think there is a warning module on that engine, it just directly activates the horn:

Disconnect both low oil sensor leads (blue) at bullet connections.
Connect an ohmmeter between sensor leads.
There should be no continuity through sensor. If continuity
exists, sensor is faulty.

Gerry

 

[repair man]

Re: Constant Alarm

Your s/n comes up as:

MERCURY - ( 50 H.P. (2000 ))
Serial No: 0T045541 Model No: 1050412WD

Parts and Service Bulletin list for s/n 0T045541:

Search Results - Crowley Marine

Service Manual is P/N: 90-852572 and if you would like a copy, drop me a PM with an email address.

Don't think there is a warning module on that engine, it just directly activates the horn:

Disconnect both low oil sensor leads (blue) at bullet connections.
Connect an ohmmeter between sensor leads.
There should be no continuity through sensor. If continuity
exists, sensor is faulty.

Gerry

Thank you !!! I will try that. Very helpful !!!!

 

[joed]

Re: Constant Alarm

Mercury oil tanks have a magnet glued to the bottom of a foam float in the tank. The magnets tend to fall off the float and lay in the bottom triggering low oil. There is no fix for it other than a new tank. You can confirm the issue by removing the tank and turning it upside down. If the alarm stops you know what is wrong.