MosesX605

My recent foray into removing my rats nest has prompted me to consider my winter running problems, which I have posted about in the past. Now the best way to ensure that I have no problems with my RX in the winter is not to drive it, and hopefully I'll have a winter beater this year, but it's not a given, and my car HAS to be able to operate in the winter months if necessary.

That being said, on to the mystery:

I have been having some problems running my car in the winter for the past two years. Problem one is that the tank doesn't vent properly in the cold weather, causing vaporlock in the lines and starving the engine of fuel. Problem two is that the primary venturies coat themselves with a large amount of frost, which doesn't go away until the underhood temps are raised by a significant amount of driving.

Now I traced problem one to the rats nest, part of the reason I finally removed it this summer. If I left the fuel tank vent line on the firewall open to the atmosphere, the engine never ran out of fuel, leading me to believe that my ventillation and check valve was kaput. Another hint in that direction was that my oil filler neck was accumulating moisture and the dreaded lung mustard, even though everything was hooked up correctly. My guess is taht since the ventillation and check valve wasn't operating correctly, moisture was building up in the vacuum lines of the rats nest, and would freeze in cold conditions. So now that I've removed the rats nest and installed a PCV valve, I have no more lung mustard and I assume that if I have to drive my car through another winter, it won't starve for fuel.

The second problem is far more difficult to figure. According to the guru's, carb icing only occurs at near freezing temps, not below freezing. Regardless of that, my carb ices up like no one's business during the winter and spring months, at temperatures ranging from 3 degrees Celsius right on down to minus 40. I've got my carb stove hooked up in the winter time, so there is a large amount of hot air going to the airbox from the header heat shield. Is there any other way to raise the temperature of the carb so that I can avoid icing? Aside from that, the car is easy to start in cold weather, and with some judicious use of de-icer, I can melt the frost in the venturies, but I really hate stop-gap solutions and would prefer a real, long term fix.

So, what do you think is wrong?

I have a theory that is linked to the ventillation and check valve, but it's pretty crazy. Now since there was a large amount of moisture in the lines going to and from the ventillation and check valve, they froze in the cold weather, causing the vaporlock that starved the carburator of fuel. Ok so far? Now since the carb vent was also connected to this system, could the large amounts of moisture get into the carb venturies, where the pressure drop would freeze the moisture along the venturi walls? If that's the case, I may have fixed that problem as well with the installation of the PCV valve and the subsequent removal of the lung mustard.

Does that sound plausible, or do you have other ideas?