Mercury 60hp overheat.

[ponchobro]

I have a mid 90's 60hp 3cyl 2 stroke that overheats but has a stream flowing from the tell-tail. Could it be a thermostat?

Thanks

 

[carholme]

Re: Mercury 60hp overheat.

What is your engine s/n? How do you know it is overheating? Do you get the momentary test beep when the key is turned on and do you get the steady warning beep that indicates overheating?

Have you checked the oil injection system? could be low oil, bad sensor in tank or warning module failure?

Gerry

 

[Texasmark]

Re: Mercury 60hp overheat.

The stream from the tell tale may come from the exhaust manifold water jacket like it does on my 90. Look at the flat plate on the left (Port) side of the engine and if it is so plumbed you will see a nylon rt angle fitting and the hose that goes directly to the lower cowling adapter and out.

That is a separate cooling loop from anything that the thermostat controls. You have to have fresh cooling water to the exhaust as long as the engine is running to keep from melting the paint and other such stuff. Just because you see water out the tell tale doesn't mean that your impeller is doing all that it can do. It may need replacing which would/could help in an OT situation. I replaced mine (impeller) recently with a respectable stream and upon removing it the ears were bent back in what I call a "set" caused by sitting too long in the eccentric water pump housing. That obviously can't pump as much water in a displacement pump which you have at low speeds as one where the impeller blades seal to the side of the pump housing and could cause/contribute to an alarm.

The stat, if like mine is stamped 143F for the opening temp and is accompanied by a pop-off valve used to bypass the stat at rms in excess of 2500. If your stat were stuck shut and you got an OT (not oil as mentioned) alarm, getting up on plane and waiting about a minute or so the engine would cool off via the pop-off and the horn would silence. Slowing back down below 2500 would cause the alarm to reinitiate after a couple of minutes. I bought my boat used and on my first outing I had the above symptoms, besides the manual describes the operation. I got home, took the stat out and put it in a pot of boiling water and sure nut it was stuck shut. New stat and no problem since ('04 to '13).

HTH,
Mark

 

[ponchobro]

Re: Mercury 60hp overheat.

The engine SN# is 0G107869. The alarm was steady and then was beeping. the water from the tell-tail was cool.
Thanks for your input.

 

[Faztbullet]

Re: Mercury 60hp overheat.

Yes them t-stats as bad about holding debris...

 

[carholme]

Re: Mercury 60hp overheat.

Your s/n comes up as:

MERCURY - ( 60 H.P. (1994 ))
Serial No: 0G107869 Model No: 1060411PD

Parts and Service Bulletin List for s/n 0G107869:

Search Results - Crowley Marine

If you would like a copy of the service manual, PM me with an email address and I will send it to you.

From the manual:

When ignition key is initially turned on, the warning
module will briefly provide a self test of its engine overheat
warning system - a brief continuous BEEP tone,
followed by a self test of its low oil warning system - a
brief intermittent BEEP-BEEP tone.

Gerry

 

[joed]

Re: Mercury 60hp overheat.

Could be your impeller. I had almost the same engine that would overheat when idling but would be fine at high RPM. The impeller was stiff and not pumping enough water at low speed. AT high RPM everything was fine.

 

[Texasmark]

Re: Mercury 60hp overheat.

When ignition key is initially turned on, the warning
module will briefly provide a self test of its engine overheat
warning system - a brief continuous BEEP tone,
followed by a self test of its low oil warning system - a
brief intermittent BEEP-BEEP tone.

Gerry

Gerry,

Where did you get this information? My '02 90 hp does neither nor can I find it mentioned in my service manual.

Thanks,
Mark

 

[carholme]

Re: Mercury 60hp overheat.

Well, I don't imagine you can find it in your manual. They are two different engines, 60/90 hp., 1994/2002 and two different service manuals, 90-817643 and 90-830234.

The warning system described in post #6 is from section 3D1 of the 90-817643 manual.

Your engine (Section 3C10) is described as:

Low Oil Condition – Indicated by an INTERMITTANT
BEEPING sound.
Overheat Condition – Indicated by a CONTINUOUS
BEEPING sound.
WARNING HORN SYSTEM CHECK
1. Turn ignition key switch to “Run” position.
2. Warning horn will BEEP once.
3. Turn key switch to “Off” position.

Gerry

 

[Texasmark]

Re: Mercury 60hp overheat.

Well, I don't imagine you can find it in your manual. They are two different engines, 60/90 hp., 1994/2002 and two different service manuals, 90-817643 and 90-830234.

The warning system described in post #6 is from section 3D1 of the 90-817643 manual.

Your engine (Section 3C10) is described as:

Low Oil Condition – Indicated by an INTERMITTANT
BEEPING sound.
Overheat Condition – Indicated by a CONTINUOUS
BEEPING sound.
WARNING HORN SYSTEM CHECK
1. Turn ignition key switch to “Run” position.
2. Warning horn will BEEP once.
3. Turn key switch to “Off” position.

Gerry

Well that's not in my manual either. Since I had an OT alarm the first time out I know my boat's module and sensor work. I have had 2 controls, 2000 and 3000 and neither beeped the first time.

Mark

 

[carholme]

Re: Mercury 60hp overheat.

What is your manual P/N?