Temp sensor issues

[duffymahoney]

Hello all.

My boat sometimes goes above 200 degrees. I don't get alarmed, because I can touch and feel all parts of the motor and they are warm- cool to the touch, this is after replacing the thermostat twice (180 degree) and impellar once. Also my heater isn't pushing super hot air, even with the Y pipe. I surf on a cold lake. I am assuming it's wrong, because of these facts. The thermostat opens and drops the temp down fast as well. I want to get this fixed though, since something isn't correct. Should I start with the sending unit? Any clue which one is the one to buy? 2005 24v with marine power 340hp. I am thinking it's not the gauge since it corrects itself with the thermostat opening and closing, and when it's first started cold the temp is close to my water temp gauge. It's also seeming to get worse. I also checked the strainers. Which are totally clear.

Thoughts?!!

[topaz surfer]

If its intermittent and the boat seems to run fine I would think its a problem in the water cooling flow. Bad impeller, clog in the water cooling hoses maybe from an old impeller that lost a chunk in the system or a bad thermostat. I have replaced a couple of bad thermostats in a row right out of the box. Also make sure your not leaking any water in the cooling system as well.

[duffymahoney]

If its intermittent and the boat seems to run fine I would think its a problem in the water cooling flow. Bad impeller, clog in the water cooling hoses maybe from an old impeller that lost a chunk in the system or a bad thermostat. I have replaced a couple of bad thermostats in a row right out of the box. Also make sure your not leaking any water in the cooling system as well.

Not intermittent and it's been an issue since I got the boat, it's just getting worse. I really think it's the sensor. I will bring my infrared temp reader on the boat tonight. See if the cooling system is seeing the same high temps the gauge is seeing.

[topaz surfer]

That is a good tool to use. I use mine for many things . Yeah you might just try changing the sensor to eliminate that possibility.

[duffymahoney]

Well the temp that the infrared was reading was around 50 degrees or so lower. When my gauge said 175 I could touch every part of the motor. All hoses, metals etc.. Hottest fitting was the heater fitting at 135 when the gauge said 175. Anyone know the sensor model?

[topaz surfer]

Sounds like the sensor or the gauge. Well at least thats good that its not really getting that hot.