I just wanted to post this in case I could save anyone some time and money!

I bought a rebuilt carb from Petroworks and put it on in the summer. Carb bolted right on and the truck ran great. Winter came, (in AZ) and temps hit 40 or slightly less. Truck would not start. It acted like it was spark issue. Choke and everything worked correctly.

Pulled plugs and they looked lean.

I adjusted the air/fuel mixture screw out 2.5 turns and the high idle screw in about 2 turns. Started up in 40 degrees the next morning. I'm guessing you may need the high idle turned in more the colder it is.

Good luck and hope this helps somebody!