Read through the thread briefly and did not notice this.

Very good chance you have a tank full of gas formulated to run in a different season. Different vapor pressures. Try draining out the gas and storing it. Get some fresh gas from a different station (if you just purchased this).

Come summer time blend in the old gas and use it up.

http://agri.nv.gov/Measurement_PetroleumGasoline.htm

http://www.waynesgarage.com/docs/gasoline.htm#season

http://mda.mo.gov/weights/fuel/testing.php

It's probably worse than that. After reading a few other threads I came across one that jogged my memory. The last time I got gas for the truck (before this problem showed up) I recall the delivery truck was there at the station delivering fuel while I was getting gas!
Also this truck has an aftermaket tank which holds I believe 40 gallons. So I never have filled it. Most of the time the tank is for sure less than half full and most of the time 1/4 or less. So I will fill it next time she goes to town.

You dont need to drain your tank. You should do as Dan sez. I would also change your fuel filter as it is likely full of water and crap.

Good thinking with the propane heater......

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Yeah....Im the one who destroyed this rare, vintage automobile.....