Carter GTR Temp Control Unit?

[OnTheRock]

After a lot of troubleshooting, replacing the cylinder head temperature sensor and having to directly wire the radiator fan to the battery because it wouldn't come on, I've come to the conculsion that my temp control unit on the 250 GTR is bad, because the temperature indicator light doesn't seem to have any logic to its coming on. I KNOW the engine isn't hot. I used a temperature gun for about 2 weeks on every ride to get some good numbers of how the buggy is running.
Highest temp recorded was before wiring the rad fan - 186 C
Highest temp recorded after rad fan was wired directly to battery - 150 C
The engine is pushing coolant properly, and it is not over heating, yet the engine temp light comes on more times than not.

So the short version of all of that is:
1) Does the conclusion I've made about the Temp control unit make sense?
2) Without Carter carrying any parts, where can I get a new one? Is this part shared with any other buggies? I know the HH250 shares a lot of common parts, would that work?

[SYCARMS]

I would get rid of the idiot light and install a temp gauge. Auto Zone will have a electric gauge complete with sending unit. The light comes on when the engine is overheated whereas the gauge will let you know prior to overheating. Also if the sender goes bad you just purchase one for that gauge.
TOM

[GX150]

Those temperatures are too hot for a water cooled engine. They should be running under 100* C.

[SYCARMS]

Wow !! Good catch GX150, I missed that he was quoting in C instead of F

TOM

[OnTheRock]

I should clarify, the 150 degrees is on the exhaust side of the cylinder head. The radiator's hottest peaks at about 80 degrees at the very top, and it's never more than 40 down bottom
If the engine wasn't cooling properly wouldn't the temperature continue to rise? It never goes above those temps, even after an hour of going basically flat out.

[SYCARMS]

Something don't sound just right. The thermostat will not open until 180 deg. So the water comming into the top will be 180 deg. plus more like 195deg. As it runs thru the radiator the bottom may reach 150deg. but not much lower. The head will be the hottest at the exhaust side say 220 deg. I state this as the norm for these buggies from vast experiance. Your temps just do not sound logical. Just how cold is it in Newfoundland these days. The temp measured at the bottom of the radiator will never be less then ambient temp outside. We in Mississippi do not get very cold in winter with the average daytime temp around 40 deg. But still I will measure much higher temps then you have measured. I have seen the infrared thermometers go bad especially the less expensive ones. A top of the line one will run you $250.00 US dollars. I would check the calibration of your thermometer.

TOM

[OnTheRock]

Are you talking in Fahrenheit of Celsius? Because My temp readings are all in Celsius. The infrared thermometer we were using was pretty much top of the line so I doubt that's the issue.

[SYCARMS]

Originally Posted by OnTheRock

I should clarify, the 150 degrees is on the exhaust side of the cylinder head. The radiator's hottest peaks at about 80 degrees at the very top, and it's never more than 40 down bottom
If the engine wasn't cooling properly wouldn't the temperature continue to rise? It never goes above those temps, even after an hour of going basically flat out.

OK, prior it was asked if you measured in far. or cel and you had no responce then mentioned 150deg. We here in the US hardly ever refer to the metric system, so you have to be clear on that. Now the temps you are refering to in cel. sound good. The sending unit is probebly bad. Still I would go with a gauge since you can see when the temp is getting up above normal for with (as we call it an idiot light) will tell you only when you are already overheated which is not a good thing for the CN/CF 250 engine. Sorry for the mis-comunication, I should have assumed with being from Newfoundland that your referance was to celcius. NO I am not Blond. LOL

TOM

[SYCARMS]

Wait maybe I am Blond since I now have noticed your earlier referal to celcius as did GX 150. Boy did I screw that one up. LOL

TOM