Bad temp gauge (Attn kjgmh)

[Muskieguy]

I still need help with a problem. My temp gauge is still registering <100 degrees when I took it to the river this weekend. I followed the advice of kjgmh in this post http://fishingminnesota.com/ubb/Forum9/HTML/003359.html and the results were.

Removed the sender wire from the motor and touched it to a ground, which caused the Temp Gauge to read full HOT. (from what I understand tells me the gauge is OK)

Started the boat and poured HOT water into the earmuffs and after about 10 minutes the Temp Gauge read about 160. My boat has a 160 degree thermostat. (to me that means the sender is ok?)

Could I possibly have a thermostat problem? Is it possible that the tstat is stuck open which would never let the motor heat up to correct operating tempature???(constantly pulling cold water into the cooling system, therefore the operating temp of less than 100 degrees??)

HELP PLEASE, this is driving me nuts.

Thanks,

Muskieguy............