cold weather performace

[John Martin]

I took the car out today , it ran good but noticed if I hit the gas hard it broke up some just after the acc shot . How does the cold air change the mix ? Would it make it lean?

[Michael C Henry]

I would think it would lean it out some. Know how you use the choke to get cars going in cool weather?

[coosawjack]

Probably ice from the venturi....This happens a lot in cooler wx with outboard motors??

My $.02....

Coosawjack

[JAM1775]

Hi John,
I have found ice in my venturi and it became stumbly, especially at idle , then I pulled the air cleaner off and saw the ice. As far as jetting........I would venture you could use at least one jet front/rear if you are out in 30-35 degree temps when the motor is tuned to run 75-85 degree summer temps. 50 degrees is a real big spread but I am not sure it would cause breaking up on the way up. If you needed 2 jets front/rear you may hear it breaking up slightly up top and near the redline. I am not sure if your symptoms are from the cold unless you are already on the lean air fuel mix borderline. Gotta get the scarf and go out again there fella !!

[flipper35]

That's why small planes have a carb heater too. The temp drop and drop in air pressure going through the venturi is ideal for forming ice.

[Burgs]

Colder air = dense air = leaner,... not necessarily too lean, but yes, leaner. I'm not saying that's why your breaking up, I'm just saying...