overheat buzzer with strong tell tale

[dragula65000]

1989 175 johnson and went out this morning and i started hearing a steady buzzer. Went home and I checked the book and it said I have an overheat warning. I have a strong steady flow coming out of the tell tale, and I pulled the thermostats, and they still looked brand new. 1 year old. I let the engine cool down for 3 or so hours and started the engine and within 40 seconds or so, the buzzer went off and I can still hold my hands on the cylinder covers, barely warm. The starboard was a little warmer than the port, but not much. Can this possibly be a sending unit? Just taking suggestions. Do they still make those temperature crayon pens the book mentions?

 

[Saskatoon2005]

Re: overheat buzzer with strong tell tale

You should be able to purchase infered temperature sensers, where you just point it at the item you want to measure and it gives you a digital readout of the temperature.

After you get that fixed, buy and install a temperature gauge into your dash, either a water temperature, or a dylinder head temp gauge. Another safety feature is a water pressure gauge. The water pressure works well with the temperature gauge and between the two you will be able to find a weak impeller long before it cause you to burn up your cylinder head...Good Luck

Patrick

 

[emdsapmgr]

Re: overheat buzzer with strong tell tale

You have done some good investigation. If you can hold your hand on the engine for 20-30 seconds, it may not be overheating. Could be that one of the two head sensors is bad-shorted to ground. Try disconnecting them one at a time and see what happens with the horn. There is a locking connector 3" from the sensor under a black rubber "hose." I believe the crayons are still available, but are rarely used anymore. You may find that purchasing an inexpensive infrared temp gun is as cheap as 2-3 crayons.