My truck starts fine, but then I have to hold my foot on the gas for about 15-20 minutes so it won't shut off. It also backfires til its warm. I found that my throttle solenoid has the wires cut off, could that have something to do with it? Your talking to a rookie here, so explain it as easy as you can. Thank you in advance.

 

Do you have a choke on the carb at all? It should idle fast on its own till it warms up.

 

https://www.ford-trucks.com/dcforum/User_files/mil1ion/3bd7962930da34f5.gif
Sounds to me like the fast idle circuit on the choke accelerator linkage is binding and not allowing the linkage to move smoothly
allowing the engine to run at say 1100 Rpm during warm-up.
If it is binding ,squirt some WD-40 in around the linkage to maybe loosen it up.

Also check your choke spring to see if it's hooked up.
loosen the 3 screws that hold the choke housing ring ,then slightly turn the housing clockwise or counter-clockwise to see if this action moves the choke butterfly on top of the carb
If it works take it back to the mark it was set on.

Next time is has sat for a while.
Pop the hood ,take off the air cleaner and move the accelerator
linkage like you were revving it as high as it will go.

See if the butterfly AUTOMATICALLY closes.
If not, get back to us.


I hope you know what I'm talking about?
Behind the black choke spring housing there are a couple of linkages.
Lift upward on the one that controls the butterflies on the carb.
This action will close the butterflies a little.
See if engine will run faster than the stalling speed.


Dennis

78 F-150 429CJ 465,000 KM.(Original Owner)
68 Mustang 289 Sunlit Gold 80,000 Miles(second Owner)
64 1/2,260 Pre-World's Fair Mustang #8092
64 Fairlane 500 S/C,waiting for a 390 4-Spd

If The Girls Don't Find You Handsome,
They Should At Least Find You Handy!

 

Have you had this problem for awhile or has it just become noticeable with the onset of cooler weather? If it has some connection with cooler weather-below 45F-it could be that your carb is icing. Check to be sure your heat stove tube is connected between the air filter and the manifold. I had these symptoms with my truck until I got rid of the chrome open element air filter, installed an enclosed filter and rigged up a heat stove around one of my header tubes. It now behaves as tho it is fuel injected in the cold weather.

DannyP
89 F-150 4x4 former EFI I-6 now carbed 351W, Edelbrock heads,cam,intake,carb.
MSD 6A, ZF, Sterling 10.25 with 3.55L's.

 

I was told my choke pull off isn't working. Everything else is moving freely, and it only does it when the weather is cold. Once it's warmed up, it runs like a champ. Someone told me that my thermal choke needed readjusted? How does this thing work? (thermal choke) Thanks for the help so far.

 

Do what mil1ion said and push the throttle open when the engine is cold. Take the air cleaner off and see if the choke is closed. If it is not, loosen the screws on the round black choke housing and turn it "richer" as it is engraved on the side.

 

I did what he said, and it went shut. Now what do I do?

 

Did you try it? What happened? Will it run better now?

 

https://www.ford-trucks.com/dcforum/User_files/mil1ion/3bdba0cd79e769ee.gif

When the Engine is Cold.
Hold the linkage as far as it will go to the Open position,
Does the Butterfly *Open* just a little bit, 1/8" ?
If so, that's good!
If not, the black choke assembly needs to be turned a little way back toward the lean dircetion until the Butterfly opens about an 1/8" with the accelerator linkage fully open.

Now, Start the engine and watch to see if the butterfly slowly Opens More and More to end up being straight up & down.

If it doesn't do it automatically,as the engine gets warmer,
Every once in a while give the accelerator a little rev with your hand and see if the Butterfly moves closer to Wide open.
If it doesn't the choke lever of the linkage is proably binding and needs some freeing up, then lubrication.

Get back to us , tap tap tap......
Dennis

78 F-150 429CJ 465,000 KM.(Original Owner)
68 Mustang 289 Sunlit Gold 80,000 Miles(second Owner)
64 1/2,260 Pre-World's Fair Mustang #8092
64 Fairlane 500 S/C,waiting for a 390 4-Spd

If The Girls Don't Find You Handsome,
They Should At Least Find You Handy!

 

Sounds like a blown power valve, also known as the enrichment valve, to the front bottom of carb, square approx. i inch cover, just replace(autozone sells them) and see, if it helps, take back apart and rebuild it, good luck.

 

Ford carb chokes go bad bigtime.....retrofit a manuel choke on them....its well worth it!!!!

 

I agree, but when the wife or a friend wants to borrow the truck, and you have to have a 15 minute explanation on how to start it, they usually say thanks but no thanks, or the wife will say "sell that piece of junk and buy something I can drive".

 

You are right Franklin2, so that's what I did, I bought a 1988 F-350.
Thanks for all your help folks, but other things started going wrong, and it just wasn't worth it.