serious carb freezing problems

[Khare]

Hey guys. now winter is here i have put my hot air feed and foam pipe back in place to stop carb freezing, but it hasnt helped its still really serious. Can a badly tuned carb cause this? i know its running very rich and idle is a tad high. I got a weber 32/34.

[DarnPB]

I think you can change the chokes on these carbs, so have you got the correct chokes installed for your engine application? If the chokes are too small, then the pressure differential accross the chokes will be high causing a higher velocity airflow, reducing static pressure and thus temperature. You will also lose a little power as the engine will not breath sufficiently.

[Khare]

the choke size is correct. i didnt get carb freezing last winter when i had bought the car. and i made a run to gatwick last year and it snowed for hours and temp was absolutly freeezing, and i didnt get carb freezing...yet today, its raining, not extremly cold, but on the chilli side, and i got carb freezing on the way home

[Jay]

You got carb freezing while the car was in motion and the engine already warm?

You sure the hot air feed has not perished or come off again? Is the seal tight?

The other morning when it had snowed overnight, my bonnet had lumps of ice on (as the rest of the car did as well), the car started first time. Do you ever use Redex to clean the carb/engine?

[Khare]

You got carb freezing while the car was in motion and the engine already warm?

You sure the hot air feed has not perished or come off again? Is the seal tight?

The other morning when it had snowed overnight, my bonnet had lumps of ice on (as the rest of the car did as well), the car started first time. Do you ever use Redex to clean the carb/engine?

yup. engine warm, had been driving for about 20/30 minutes.
hot air feed i bought some new aluminium ducting the other day and put it on so its in good conidtion. Its not airtight seal, but its sealed enough to get hot air in the carb. i havent used redex in about 2 months but i will be using it this week sometime. car starts first time everytime, carb freezing only when its hot, doesnt happen when its dead cold. I usually pull up somewere, let it idle cough for a min, give it a couple of revs, although when i do it bogs down/cuts out, turn it off unless its already cut out, wait 2 or 3 mins, turn it back on, and its good for another 10/15 mins.

[Jay]

Get the timing setup, when last did you change spark plugs and fuel filter?

[Khare]

Get the timing setup, when last did you change spark plugs and fuel filter?

timing is spot on, was set up a couple of months ago.
Fuel filter and spark plugs were changed about 6 months ago, along with dizzie cap and rotor. although im gonna give it another full service in a month or two.
dont think its to do with servicing parts though. its more carb related in my opinion. When idleing, it has a very slight misfire, which yes, could point to timing, but the power is still there and as i said, it was done a few months ago.

[Dolly]

my driver used to do it with the pierberg, i had a quality hot air feed and set the carb up my self, but still had the problem. i discovered where the hot air feeds into the intake system, there is a vacuum operated flap. obviously should open close as req. the diaphram had failed and this flap was stuck closed so no hot air could get in. i put a screw through the casing, jamming it open so i always had hot air from the exhaust flowing .

[Khare]

thats the awnser i wanted. i put vac pipe back on but i dont see how it controls the flap
so keep the flap up so less cold air comes in yea?

[Khare]

sorted. hopefully anyway. Put some screws jamming the flap, so its 3/4 hot air and 1/4 cold. Should be enough to avoid carb freezing.