I finally get a chance to work on my junk today...

1979 F150, 351M with a rebuilt 2150 carb. The choke is connected to the metal tube from the intake manifold, and has a clip for a heater hose, but the heater hose is NOT in the clip. There are no electrical connections.

When the engine is cold, I press the pedal to the floor once and crank the engine and it fires right up and the high idle works fine. It runs smooth and never dies. But, if I touch the pedal after it's started, even if it's just a couple seconds, the fast idle will turn off and it will just idle slow.

Also, the choke flap isn't opening up all the way after it's warm. Pic http://i44.photobucket.com/albums/f2...0-13-05013.jpg

After the engine is warm it will "ping" while accelerating somewhat fast or climbing a hill.

There is a dead spot if I try to accelerate too fast. Someone told me to check the accelerator pump, so I'll do that today.


Does my choke need adjusted? I found a choke adjustment procedure by fmc400 while searching, but my engine is already warm, so I'll try it some other time.

 

Sorry but I have to disagree a little. The picture shows that the choke is not opening all the way to the vertical position. I would suggest that if setting the choke cold, you should turn the choke housing until it is just nearly closed. Leave a 1/16" gap. Then when the engine is warm, check to see if the choke plate is fully vertical.

As to the fast idle: There is a link from the choke butterfly to the 'fast idle cam.' It has it's own adjustment screw. The cam part has steps to hold different speeds which you can select by bending the link. Fine tune it with the adjusting screw so that you maintain fast idle so that the engine doesn't bog when cold.

Your carb has both an accelerator pump and a power valve. The accelerator pump shoots in jets of gas as you mash down on the pedal. You should be able to see this in action looking down into the carb. (Just do it once with the engine off.) The power valve is an enrichment circuit that works when accellerating. One or both of these may have a problem causing it to bog from being too lean. If it has been backfiring through the carb it may have blown out the power valve.

 

So, after the engine is warm I can adjust the black choke cap so the choke plate is vertical?

When I accelerate, if I push down too quickly on the pedal it will just go dead for a second or two, then take off like crazy. Under normal or slow driving conditions, eveything runs fine.

 

Yes, I would make that adjustmet. Just recheck again with the engine cold, just to make sure it starts ok. But having that plate vertical will help with your milage.

That bog you describe may be the accelerator pump or the power valve.