Overheat Alarm

[grbeasley]

I have a 1994 Mercury Tracker 40hp motor, SN 0G100240. The overheat alarm keeps going off occasionally for no apparent reason, as I can hold my hand under the pee stream. The alarm is a solid beep, not oil level. The bigger the load in the boat, the more it goes off. It never goes off running in a garbage can. If I fish alone, it hardly ever goes off, but that's no fun. A boat mechanic told me that they only put this alarm on this motor for one year and if it were him, he would simply remove it. I tried unhooking the end on the back of the motor, but it had no effect. Could there be other reasons for this alarm? I read where the alarm should sound when you turn the key on, but this is hit or miss on mine. Any ideas? What if I snip the wires running to the alarm under my dash? Will that affect the rest of the wiring harness? Any help is appreciated, I am going crazy trying to figure this out.

 

[racerone]

Note----The " pee stream " may be cool even though the motor is overheating !-----I would first look into replacing the water pump impeller !

 

[grbeasley]

I have....twice. I have had this problem intermittently for a couple years. What about clogged thermostat or poppit valve, if mine has one. I am really searching for something other than taking it to the mechanic and saying fix it, when they can't duplicate the problem at their shop.

 

[racerone]

Salt water operation ?-----There is a plastic piece at the top of the water tube with a grommet seal.----A lot of work to inspect / replace it.------That plastic piece is also NLA so you would have to make one.------Perhaps install a water pressure gauge on your motor and observe / note pressure in various operating conditions !

 

[grbeasley]

Never been in salt, just a little brackish (St Johns River south of Jacksonville). Thanks for the suggestions. I will give it a try.

 

[Silver Eagle]

take a garden hose .put it on straight stream, shot water into your water inlet ,do that for a while .It should clean out what is plugging the inside up. .Could be a spider that built a nest inside the water inlet. never know.

 

[Faztbullet]

1) Don't take any more advice from that mechanic about alarm or anything else
2) Whats this mounted on?
3) Has it ever overheated before now?
4) Is the grommet in the water pump base?
5) Have you installed a depth finder od speedo lately?

 

[grbeasley]

I think you have some solid advice to stay away from this mechanic.

This motor is on a 1994 17ft Tracker Bass boat. The alarm has been going off intermittently for a couple years. I thought I had it conquered last year after impeller #2, because it almost never went off. Last year my fishing buddy was unable to go with me. When he started going again this year, it began occurring again. I went by myself once this year and it never happened, so I am beginning to see a pattern, I think. The motor never exhibits any other symptoms of overheating. No smoking, running rough, nothing. I ignore the alarm now as being just a nuisance, although I always put my hand under the pee-stream, just in case.. It is never too hot to hold my hand under it for several minutes. Someone posted that the pee-stream not being hot may not mean the engine is not overheating? In that case, the water must have more than one route to travel. How do you check all routes possible by the cooling water?

Your question about the grommet is interesting, since I did not replace the #2. I will have to look into that.

Thanks for your input.

 

[hardwater fisherman]

I think on most motors the pee stream is an indication that the water pump is working. But the water coming out has not been circulated. Or not fully circulated.