There's an interesting thread in the German Pinz forums about using Isopropyl alcholol to prevent de-icing. One of the guys went to the airport and asked what planes without carb heat do during the winter and it turns out they mix about .5% isopropyl alcholol into the fuel. Another guy chimed in that he just went on a long tour and that he does this and doesn't have icing problems. When I rebuilt my carbs I wrapped the intake manifolds with foam insulation to try to keep the cold air off them, but when it's -15 F this morning, I'm wondering if I need to do more. Have you guys heard about doing this? I wonder what the alcohol would do to cylinder walls?
http://pinzforum.kiruna.de/viewtopic.php?t=2329
Carbuetor De-Icing
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McCall Pinz
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Jimm391730
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Carb icing comes mostly from the water vapor in the air that condenses, then freezes in the lower pressure area of the carb venturi and partially open throttle butterfly. Alcohol in the fuel won't protect against this type of icing, that is why there is the heater hose to the air intake and the damper to help thaw out the carbs during idling.
But alcohol will absorb water in the fuel and prevent fuel line freezing (I believe that "HEET" or other fuel drying agents are mostly alcohol). Water is easily introduced into the fuel if the air is moist, the tank is low (meaning lots of air volume above the fuel), and the truck sits for many days -- each day as the temp drops the air shrinks, drawing in wet air that can condense inside the tank and gradually contaminates the gas. Keep the tank as full as possible will help prevent this during storage, as there is less air volume to exchange each day.
I have had only one incident that I knew was carb icing; on a cold winter morning with my old V8 Chevy it ran fine for about half a mile, then started running worse until it stalled a few blocks later (happened pretty quickly). I coasted to the next light, and left the engine off while it was red to allow what little engine heat that had developed to wick up to the carb. When the light turned green, it started right up and ran great from that point on.
Jim M.
712W and 710M
But alcohol will absorb water in the fuel and prevent fuel line freezing (I believe that "HEET" or other fuel drying agents are mostly alcohol). Water is easily introduced into the fuel if the air is moist, the tank is low (meaning lots of air volume above the fuel), and the truck sits for many days -- each day as the temp drops the air shrinks, drawing in wet air that can condense inside the tank and gradually contaminates the gas. Keep the tank as full as possible will help prevent this during storage, as there is less air volume to exchange each day.
I have had only one incident that I knew was carb icing; on a cold winter morning with my old V8 Chevy it ran fine for about half a mile, then started running worse until it stalled a few blocks later (happened pretty quickly). I coasted to the next light, and left the engine off while it was red to allow what little engine heat that had developed to wick up to the carb. When the light turned green, it started right up and ran great from that point on.
Jim M.
712W and 710M