Frozen Webers

The East coast is wreaking havoc on my carbs! Anyone have any advice on frozen Webers?
I am having some stalling / fuel starvation after about 10 minutes into warmup.
Just wondering if there's anything I can do, this side of little blankets for them!
This is occuring on 20-20 degree days.

Click and Clack just had an answer for something like this. Off course it wasn't webers or a porsche but the answer is to get some warm air into the intake. I wonder if you could do that?

First, I'd check for moisture in the system.
Second, Carbs don't adjust themselves for altitude of temperature which are basically the same thing. They affect air : fuel ratio. So, you have more dense air at colder temps, therefore you have a leaner mixture. The jets in the Webers are easy to change and not outrageously expensive either. The hot air idea is also good, but beware of the possibility of condensation freezing. (IE, hot moist air hitting cold carb parts.)

aaaah, it's times like this that i'm glad i have fuel injection

sorry, had to put that jab in there for the people still running 100+ year old induction technology. honestly though, there are block heaters and other devices meant to keep the carb butterflies from freezing. the other thing to do is to try to keep the car as warm as possible when it is not being driven. when the engine warms up, you should not have a problem with the icing as you would when it is being first fired up and driven away.

check this article: http://www.chevron.com/prodserv/bulletin/motorgas/sidebars/carb.html

and good luck!

obin

Of course air intake heating reduces horsepower because the air is less dense....

My Ducati 900 had icing problems in any less than 50 degree F weather.... Warm the engine more before leaving... There are also some kits to transfer heat to the carb body too....

Carb icing can be a problem even on warm days if the humidity is just right. This is because there is a temperature drop in the carburettor's venturis when it is in operation. Aircraft engines use a carb heat or "alternate air" switch to alleviate this problem if the pilot suspects carb icing to be a cause of lost power. Usually this system just takes heated air off of the heater boxes and introduces it into the induction system. Again, there is a loss of power because warm air is less dense than cool air, but it is better than having the engine choked right off!

Air cooled VW engines use heat riser pipes that circulate hot exhaust gas right under the intake manifold plenum to prevent carb icing. I have a few buddies that tried running their dune buggies without these pipes and they couldn't get very far on some days.

One thing I learned from their misadventures is that if you pull over at the first indication of carb icing, pull off the air cleaner and look down the venturi, you can actually see ice forming inside. I have never actually seen this on an airplane because I wasn't too crazy about sticking my head outside in flight. Just remember to turn the engine off and don't look straight down the carb, lest it backfires and takes your eyebrows off!

VW's with dual carbs do not require any kind of extra carb heating because the heat conducting from the heads through the stubby manifolds keep the carbs warm enough. I suppose a 911 engine's carbs are able to drop the venturi temperature more, and the engine ends up with carbs on the rocks.

Maybe you could tee off some ducts from your exhaust heaters and direct them into your air cleaners or something. If you wanted to get really fancy, you could make the system with a cabin-controlled on/off flapper valve so you don't have to worry about the power loss when you don't need it.

Thanks to all for the feedback. I think the conditions have become just right for this syndrome here on the eastern tip of Long Island. The air is incredibly humid, and now very cold as well.
It is just a matter of getting the motor a bit warmer before heading out.
Though the cockpit flapper idea is pretty slick!
p.s. Webers rule!

Injection is modern and convenient (untill it breaks), but it is also complicated and damned ugly. Webers are asthetically pleasing and give the car that "hot rod" flair and sound.
I ran mine all year round on my old '73T. Just warm the engine a bit longer before you take off. How about that Indycar style start up on cold says? Man, that sound is like no other!