Can't get my 312CL to warm up to operating temperature.

Happy New Years Folks! Looking for any ideas you guys might have concerning my current headache. My 312CL doesn't want to warm up to operating temperature. Seemed like a no brainer, must be the thermostat is stuck open right? Ya, never seems to be that easy for me. Took the old thermostat out and placed it in pot of water right beside the new one and heated it up. The way they opened and closed was pretty close to identical. "Now," I know I'm in trouble, but I put the new one in anyway, along with the new seal on one side and new gasket on the other side. I let it run for a couple hours at about 1/2 throttle, but it never came out of the white and made into the green on the gauge. I thought maybe the sending unit or gauge might be screwing up, but checked the temperature of the casting that holds the thermostat with my infrared thermometer while the machine was running and it was only 130 deg F.

Any thoughts would be appreciated!

Thanks,

Mike

Can't get my 312CL to warm up to operating temperature.