Propane Freeze?

I have an International 500 Payloader. It runs on propane. I believe I have frozen the fuel line or converter. What is the best way to test and or thaw it out. I have let it set for many days but the temp is not getting much above freezing. When I crank on it you can smell propane I have spark. I've got a block heater

OT: also got one of those cheap Harbor freight on board battery chargers seem to do the job.

If it is flooded with liquid propane, then using a hair dryer to warm the vaporizer has always worked. The 2 pickups and 2 tractors I run on IMPCO fuel systems will usually start at 0 with only a good primer. At 20 below or colder where you get almost no propane vaporization, I have found that a shot of ether in the air intake will get it fire a few cylinders which seems to be enough to keep it running on a pretty cold/lean propane mix.

When you do get it running, let it idle dead slow until the coolant warms enough to keep the vaporizer from freezing.
The engine coolant heater will usually also warm the vaporizer for easy winter starts.

I'm still not entirely sure at what temperature these systems start to act up, but low 20's seems to cause me problems here. Assuming the LP is not vaporizing and you are getting liquid, somehow you need some heat on the fuel system.

I leave the tank off on mine and put it inside, install it when I need to start the tractor, tent off the engine compartment and get some heat going, even locally onto the vaporizor/carb via say a wagner heat gun, what have you, just use care, it does not have to get hot, just warm. I don't like open flame due to the fuel involved, make sure you have no leaks, even that heat gun would set it off I supppose. Once it fires and you can keep it running, it should have a coolant line circulating through the vaporizor, once that coolant it warmed, the vaporizor will stay warm. I've had my tractor out in below zero weather, but I started off from a heated garage, never had any trouble that way with the fuel system, but from a cold start it is a different story, also found that putting a rebuild kit into the vaporizor made a difference on fuel consumption and cold starts, mine was leaking internally, seems a little easier to deal with in the cold now.

What you are experiencing most likely is flooding caused by not having enough heat available to vaporize the fuel before it leaves the converter. Propane expands 270 times it volume when changing from liquid to vapor so just a few drops of liquid in the mixer will cause the fuel mixtures to be too rich to run. When it is flooded, shut the fuel off at the tank or fuel shut off and crank the engine until it fires. It may run a second or two as the flooding clears. Then open the fuel and try restarting it.