Carb icing??

Ok, I've got a question. My 225 has a 2g rochester, rebuilt it back in the summer. Been running really well. Couple weeks ago we had our coldest weather of the year. Went out and cranked it when it was about 25*. It idled good for about 5 minutes then I had to keep it off the idle circuit to keep it running. I drove it for about 8 or 10 miles and when I got home it idled just fine. My question is, is that cold enough for icing even with the heat under the hood. Thanks for any ideas and opinions

 

Electric choke? I’ve been struggling with the same problem since the air is so cold and the choke was kicking off before the engine was warmed up and ready for it.
You might just dial more choke on the carb and see how that does.

 

No, its manual choke. It wouldn't idle without being on the fast idle cam even at 160* water temp. ???

 

I think you're choke mech isn't working, if there is one. Needs to run a little rich 'til warm.

 

The intake manifold has passages that direct exhaust right under the idle screws in the carburetor. If those are blocked or you use a gasket that does not support getting getting heat to this area the carb will ice up.

 

Yes, this would be a good engine to make sure the heat riser is actually working, and the passage is not blocked in the manifold. Also, the TAC (thermostatic air cleaner) is a big help in getting warm air into the carb when the engine is cold. That's the aluminum tube from a stove on the manifold to the air cleaner snout.

 

My 2g rebuild kit came with a few different manifold gaskets, only one of them had the ports for the warmup passage into the cast iron base.

I also harvested an aircleaner housing off an 89 S-10 from the junkyard, and modified it to fit the 2g (forget the plastic adapters, pure junk) with some sheet steel and a small piece of exhaust pipe. Fits really well, and has the vacuum/heat activated flap that helps keep the intake air nice and warm. I have the stock exhaust on my 231 so it has the shroud around the manifold and pulls hot air from there.

With all this, and my manual choke opened all the way up, it does really great in cold weather. Went on cruise with the local 4x4 club on new years day, and had no problem at 3 degrees farenheit. Highs in the single digits will tell you if it's working or not!

 

I've had carb icing in 80*+,till car('63 Olds),& truck('74 Dodge) would stall.I'd have to stop and let them thaw.I tried everything never could figure them out???? But I've never had a prob.w/my 225,and it's driven purtnear every day