My 1971 f-100 has a difficult time keeping running in cold weather and lately in general.
Problem#1 The old girl takes a few pumps of the gas pedal to set the high idle.
The engine takes about 3-4 starts to keep running, it just seems to burn the gas in the carb off then it quits. However the carb is not empty when I have checked it.
#2 The engine races real bad when it does start and I know that this is not good for it with the lubrication aspect.
When I kick it down to early the idle is so poor it just lopes along and eventually dies with out any run on or anything, it just dies.
After 3-4 of these and my sitting in the truck for a minute or two with my foot revving the engine abit to keep it running it will finally keep running at an idle of 700-800. It finally sounds good like it should with no hesitation.
#3 When starting from a dead stop I have to feather the gas to keep it from dying in the middle of the intersection.
My points appear to need changing because on the contact pad there is a little hole in the center. Is this the culprit?
I know enough about carbs to be dangerous and some of the locals who supposedly know it all seem to think because it sounds good in their driveway, everything is good and don't want to test drive their work.

 

Check your choke pull-off.

The pull-off diaphragm should be connected to a vacuum source below the throttle plates.

The diaphragm should not leak vacuum. With vacuum applied, it should pull the choke plate open about 1/8" or so (measured between the front edge of the choke plate and the inside of the choke tower).

#2 How bad is it? What rpm? Fast idle spec is usually about 2K rpm.

#3 Does this happen all the time, or just when the engine is cold?

 

OK Bubba, I checked that the choke is getting vacuum from a copper tube that goes to the right exhaust manifold. It was S.S. but was replaced. The other vacuum line is @ the front bottom carb right hand side also and going to the vacuum advance. These are the only 2 vacuum lines I can find.
Is there a specific amt. of vacuum needed? The choke plates close when cold and open when warm.
Does the points aspect warrant any attention or does this appear to be carb related?
The idle is above 2000 I'm sure. I need to borrow my friends tach. to be sure.
And this happens most noticably when it is cold or close to being warmed up.

 

bump

 

Does it have the original air cleaner on it? It sounds like the carb is icing up because the hot air intake fron the exhaust manifold cover to the air cleaner is not working properly. Ford trucks are bad about this.
Jimmy

Some point sets come with a hole in the center. If you are not sure, I would go ahead and replace them to be safe.
The hesitation could be from the timing too low, a bad vacuum advance or a bad accelerator pump in the carb.

 

Lxman1, thanks for not letting my thread die, I have the original aircleaner with the stovepipe, and the thermostatic control is in the closed position alot, always using hot air, the timing is pretty advanced already. I have a lumpy cam and it doesn't run good in the recommended set point.The vacuum advance seems good on the dist. although there doesn't seem to be much vacuum from the carb. I will check the accelerater pump diaphram for a pin hole this weekend if the darn snow melts enough so I can get it back in my driveway. Thank you for your suggestions in this matter. I'm already saving $$ for another carb.
If I was to stick with a 2 barrel what would be a good one? And if I go with a 4 barrel, what would be a good intake and carb. combo? I guess I should mention that I have a 360 with an RV cam. Thanks for your time.
Kevin

 

Does the tube from the exhaust manifold run up to the choke housing? If so, that's a hot air tube for the choke thermostat.

Look for a vacuum tube on the pull-off diaphragm (right rear on the air horn, behind the choke tower). The pull-off is designed to open the choke slightly when the engine starts. You can test the pull-off by pushing the choke closed and applying a vacuum to the pull-off diaphragm. It should open the choke by about 1/8" (measured from the front of the choke plate to the inside edge of the choke tower).

The air cleaner heat stove motor is controlled by the air cleaner temperature sensor (ACTS) in the air cleaner housing. Manifold vacuum should pass through that sensor, and then to the vacuum motor. When air inside the air cleaner housing reaches the calibrated temp of the sensor, it cuts off vacuum to the motor and bleeds residual vacuum inside the motor to allow the diverter flap to open.

If your diverter flap stays closed most of the time, you might have a defective ACTS.