Is that front cooling fan supposed to run all the time, or just kick on when the motor reaches a certain temperature ?

 

It just comes on when the engine starts to get too hot.

 

I bought a clean used 2002 eiger with only 500 miles on it. I started it up and let it run for 20 minutes, idling when it was about 78 degrees outside. The fan never came on 1 time and the red overheat light never came on. Is this normal ? The red overheat light does come on when I turn the key on though...

 

Normally the so called idiot lights will come on when ignition key is turned on to show operator that they are working similiar to your car or truck. After the engine starts they will only come on if there is a problem. From your description looks like your good to go.

 

Looks like you didn't get it hot enough for the light or fan to come on. The switches for both are on the front of the crankcase near the oil filter. Not sure which is which, but if you jump the wires to each, one will fetch the fan on and the other the light. This doesn't test if the switches are OK but it is unlikely that both would be bad.

 

I assume, that once the red overheat light comes on , while the ATV is running , if you turn off the ATV immediately, no harm is done to the engine ?

 

Yes, provided the switch is working the light at the right temperature. May be worth checking the fan fuse, the fan should kick in at a lower temp than the light.

 

They do tend to run a little hot. I've owned a couple of them, and they do cycle on and off during normal riding. In the winter when pushing snow it'll come on fairly frequently when the machine is getting worked.