Well this isn't right...

[Rangurr]

I just heard a cool trick for testing the thermostat. put a string in the valve and then while hanging it in a pan of water hold a meat thermometer next to it and watch the thermometer and note the temp the thermostat falls off the string. I just tested a 143 degree thermostat for a outboard and it fell off almost exactly at 143 degrees.

Exactly! This is the easiest way I've ever been able to test them!

 

[OdinAF]

So.. I swapped out the clutch for a standard, and it still sets below the temp marker.
I will pull the temp and test it.

 

[RonD]

The fan clutch can't cause below normal operating temp, it only comes into play once minimum operating temp(200degF) is reached and coolant is flowing thru the rad.
Minimum operating temp is set by the thermostat.