Cold weather stalling

My motorcraft 4300 carb works fine on my 1971 T-B 429 in warm weather. When cold weather set in, it still works fine after a complete warm up. Trying to move the car before a ten minute warm up results in the engine stalling and sputtering. By pumping the gas vigorously, the car will accelerate after sputtering a bit. Each time I barely touch the accelerator this happens. After warmed up, the car accelerates the way a

429 should. I know the accelerator pump is OK and is set properly. The warm air valve on the air cleaner doesn't work at this time and I am having trouble finding a new one.
Reply to
whatsup
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I have the same trouble with my 351 Cleveland with a Holly carb. What I have to do is readjust the air\fuel mixture every time the weather changes.

Reply to
Doc

I would say the problem is related to your choke, if you have one. You need a richer fuel miture when cold weather starting, hence your pumping the gas pedal vigourously.

Reply to
Dude

Ahh yes, the old "wiggle the gas pedal on your Ford when it's cold trick" :) I remember that one well. Is there a tube with an insulated sleeve going from the choke housing to the right exhaust manifold? Ford used this for many years and I'm not sure when they stopped. The choke housing was under a slight vacuum which drew heat from the manifold to heat the choke spring. It was common for the tube to rust off of the manifold. They later went to an electrically heated choke spring, the spring housing had an electrical connector on it. It's common to lose the ground connection between the choke cap and the housing. Either failure will cause the choke to stay on too long or not open at all except via the choke pulloff. It was a common "fix" to back the choke spring off until it only closed part way when cold (or block it completely open). Engine heat would eventually warm the spring and open the choke. This "fix" would cause most of the problems you describe. You have to wiggle the gas pedal on acceleration causing the accelerator pump to supply more fuel to overcome the lean condition. Bottom line is to check all parts of the choke system and make sure they are working properly. I used to have a 71 T-Bird, nice ride. I could squeeze 16mpg out of it on a trip IF i kept it at 55 mph. Kinda hard to do with a 429 under your right foot. At 70, it would plummet to about 10 mpg.

Reply to
Tom Adkins

And dont forget the bane of allus who used to wonder WTF when the first really cold temps hit and car got cold-blooded

The exhaust "Heat riser".. That's the dealy with the counterweight and spring between the exhaust manifold and pipe, one side.

When cold is supposed to route exh through the intake to assist in vaporization.

Reply to
Backyard Mechanic

I was TRYING to forget those. Monumental PITA.

Reply to
Tom Adkins

Or just install a manual choke cable and YOU control it, rather than some spring that never works right. I put a cable on every car I own. My ford truck, my chevy car, and every car I have owned in the past 20 or more years. Automatic chokes are things that you are constantly fixing and they still never work right. Not to mention the cost of those choke coils. The one for my chevy car would have cost about $60. The cable adaptor kit cost $12, and works better.

I like being in control, and that way I can tweak according to the weather conditions. In the summer I rarely even touch it, when its real cold I completely shut it.

I have a farm tractor and that came with a choke cable. The way ALL engines should be.

All these things that are supposed to make life easier, only make life complicated.

Mark

Reply to
maradcliff

Need to know what the tube sticking out of the back of a motorcraft 4300 carburetor (ford 4-barrel)is for and is it supposed to be connected to something? right above it is the hot idle compensator! I remember that many years ago, the original Motorcraft 4300 had a rubber line hooked to the back of the carburetor but can't remember where it came from. Does the 71 Ford 429 have a spring loaded hot air valve in the exhast manifold to divert heat to the intake manifold.

Reply to
whatsup

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