Yea, as the title says, I think my choke thermostat is dead. When I turn on the car, it will not go off high idle (around 1500rpm) even once the motor warms up. I have to pop the hood, take the air cleaner off, and then push down on the rotating part between the choke thermostat and the carb body. I already sprayed some carb cleaner and that did not help. I measured the resistance of the choke coil and it was 51 ohm. According to a couple of posts I found in the search, this means it is bad, correct?

I already ordered a replacement choke thermostat just in case that is really the problem. I should get it by the 23rd. It was expensive (about $60) from Kragen and I think I ordered the last one they had since I cant reorder it. I was not able to find it at the Autozone, Pep Boys, or Rock Auto websites.

Also, is the wire going to the choke thermostat always energized with 12V while the engine is running? Doesn't it overheat if it is energized for too long and lead to its untimely death?

 

The choke heater is powered when the alternator voltage exceeds the battery voltage and energizes the choke heater relay.

The choke thermostat is made for constant duty, so no, it's not a problem to have power all the time. If it didn't have power, the choke would partially close, even when the engine was warm.

I don't recall the exact resistance of the thermostat, but it seems like it was something in that range.

 

Resistance of the choke element changes with temperature. At room temp they are usually in the 5-10 Ohm range new. Any higher than about 20-25 Ohms and they're usually shot.

They're designed to be powered any time the engine is running and only draw about one amp or so.

Five7- Oh, so THAT'S why the choke stops working if the alternator dies! All these years I never understod how that relay worked or why a bad alternator would affect it. Makes sense. Thanks for that info.

 

I have not replaced the choke thermostat but I have another question. Since the choke cam is stuck all the way up when cold, could this be a different problem? I have to push down on the choke cam to lower the RPMs when I turn on the car when cold. Stepping on the accelerator pedal does not lower the cam since it seems to be stuck all the way up.

 

If pushing on the cam weight helps for the rest of the ride then it could be just that part sticking.
Try with WD-40 or something with oil, it did the job for me at one time when my own choke was sticking and I had to push that thing to bring it down. I think it took me a couple of tries before I got it working flawlessly. Carb cleaner has no oil and evaporates completely in a short while so it won't help much (unless used in copious amounts I guess).
While 51 Ohms sounds a tad high (I can't recall what it's supposed to be) it still makes for 4 Watts of heat. It could wery well be sufficient for operating the choke afaIk.

 

I got an electronic choke that used to be on my carb, works fine. If you want to buy it, let me know.

 

My car is doing the exact same thing... any updates?

 

I sprayed the linkage around the choke thermostat with carb cleaner and it seemed to have helped. Sometimes I just need to tap the throttle a few times to "free" whatever was stuck and the idle goes down.

 

Thanks. I'll give that a shot.