I have the same carb. It sounds like something is shorting inside of the choke body. When I key mine on, it gets very slightly warm. You can hear the coil go "tangg" as it warms up after half a minute but nothing beyond that.

I'm not a fan of the action on this particular electric choke, I generally don't use it in warmer months. It works fine with the choke wired open, I just have to give it a little manual footwork for the first little bit and it will idle at 12.5:1 dead cold just fine.