Adjust thermostatic choke?

[Bobacuda]

Our ‘67 Barracuda’s junkyard 318 did not have a choke. I tried the one that was in a box of parts - nope. So I tried one from a ‘74 318 - totally nope.

So I sucked it up and bought a NOS thermostatic choke. I have installed it, and it appears to be keeping the butterfly closed. And this is in 100 degree weather - can’t be right.

I’ll be the first to admit I have never changed one of these before and know damn little about them, other than when they work, it’s great.

I noticed when I installed it there is a nut and what looks like some degrees on the side, similar to the choke in the attached photo. Am I supposed to loosen that nut and will that allow me to adjust the choke?

 

[toolmanmike]

Our ‘67 Barracuda’s junkyard 318 did not have a choke. I tried the one that was in a box of parts - nope. So I tried one from a ‘74 318 - totally nope.

So I sucked it up and bought a NOS thermostatic choke. I have installed it, and it appears to be keeping the butterfly closed. And this is in 100 degree weather - can’t be right.

I’ll be the first to admit I have never changed one of these before and know damn little about them, other than when they work, it’s great.

I noticed when I installed it there is a nut and what looks like some degrees on the side, similar to the choke in the attached photo. Am I supposed to loosen that nut and will that allow me to adjust the choke?

View attachment 1715950337

Blow a hair dryer on the coil to see if it moves when it get's hot. That thermostat might not be for your intake/carb combination but by bending the rod it may be able to be adjusted just fine. You need to take some choke away. by bending the rod.

 

[Bobacuda]

So, the nut is not an adjustment?

 

[Yote]

Can’t see back side in pic. But my ‘72 340 has the nut on one side and a slot for screwdriver on the other. I could loosen the nut slightly and adjust the thermostatic spring with a screwdriver . My choke is supposed to ‘start’ opening at 70 degrees, I used a digital infrared thermometer to determine this. Other adjustments as mentioned above can be made using the linkage rods. This worked for me, if I stated it wrong someone please set it straight.
Yote

 

[Bobacuda]

Apparently the new choke was adjusted at the factory for the Arctic Circle.

Checked the temp of the choke and the block - 84 degrees (shed is currently 96 degrees) and the choke was closed.

I adjusted it as Yote described, so now it is wide open at 95 degrees. I’ll check it again this winter.

Thanks to all for the input.

 

[pishta]

Thermostatic chokes springs all work the same way. It's the relaxed tension that sets the baseline for when the choke opens fully. You should get a good snap shut when you set the choke with the gas pedal but it should start relaxing very quickly with engine heat. Heat gun/hair dryer is a perfect tool to open the choke and then set the tension spring. When they work and step up the idle cam, they really work quite well. Some carbs will pull off automatically (rounded cams) and some will require a blip of the carb (stepped cams) to pull it out of the way of the curb idle screw.