Difficult hot start/ choke problem

[s10mk]

Hi everyone, my truck starts cold really easily, but I've been having a slight issue with hot starts. I think I figured out my problem, but I wanted to get some opinions, this is my first time working on a carberated engine. But anyway, when my truck starts, the choke is completely closed, then the vacuum break pulls the primary choke open slightly. The engine will then warm up, but the choke never moves. I read the temp just under the bi-metal coil on my intake, and it heats up to 175 degrees, but still the choke won't open, and it doesn't appear that the choke rod moves any amount at all. Am I correct in assuming that my bi-metal coil is bad?