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Ford Truck Club Forum > FORD F-100 | F-150 SERIES > 1973-1991 Ford F150



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  #1  
Old April 12th, 2012, 06:37 PM
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Default 1981 F150 4.9L Rough Idle, black smoke

Hi, my 81 F-150 has only 35,000 miles on it. It was left sitting for 5-6 years but was able to get it started relatively easily. It ran ok at idle, but would often stall when accelerating. After I changed out the fuel tank, sending unit, and fuel filter and it fired right up and ran absolutely perfect.. I parked it, and 2 hours later started it again and it suddenly idled very rough. Hadn't changed out the plugs yet, so I went ahead and did the plugs, wires, cap, and rotor. Then it ran even worse - very rough idle and had to keep foot on the pedal to prevent stalling. I was advised that the fuel pump may be bad, so just replaced it and another fuel filter just to be safe. No change, except now it is blowing very black smoke at idle and while revving the engine.

I have not touched the carburetor, other than some choke cleaner to get the truck started back when I first got the truck.

I'm not a mechanic, but willing to try anything if someone could point me from here. Thanks for any help you can suggest!
  #2  
Old April 12th, 2012, 06:50 PM
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Sounds to me as if the carb needs rebuilt or adjusted and it needs to be timed, it's easy peasy to rebuild a 1bbl, also easy to tune it.
  #3  
Old April 13th, 2012, 07:58 AM
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most deffentlly a fuel rich issue
and yes check the timing



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  #4  
Old April 13th, 2012, 12:22 PM
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Thanks guys. I noticed the distributor is locked down at the full clockwise extreme position. Loosened it and rotated to see if timing changed, but it really doesn't make a lot of difference until I go too far and it stalls.

Since it ran so terrific after the tank replacement, then instantly decided to run rough, I'm guessing the timing was probably ok and it is a carburetor issue. I've never rebuilt one, but the rebuild kit is a lot cheaper than a new carb. Is it easy enough that someone with no experience can do it? I guess I have nothing to lose by trying, as I can always buy the new one if I fail..

I really appreciate the help!
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Old April 13th, 2012, 12:30 PM
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tell us what your carb make & model # is

if its a 2150 you should not have a problem
post back and I can help you out with a DIY



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Last edited by JSoko; April 13th, 2012 at 12:32 PM.
  #6  
Old April 13th, 2012, 12:34 PM
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They are easier than most carbs, probably easier than a 2150 2bbl and those are easy, I tried a 4bbl once and didn't do it right.

More than likely your float is bad letting it flood out, hence the black smoke, should be easy to rebuild the whole thing, there really isn't anything complicated to those 1bbl carbs.
  #7  
Old April 13th, 2012, 12:36 PM
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Quote:
Originally Posted by JSoko View Post
tell us what your carb make & model # is

if its a 2150 you should not have a problem
post back and I can help you out with a DIY
It's a 1bbl J.
  #8  
Old April 13th, 2012, 12:43 PM
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I'm getting rebuild guides hang on.
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Old April 13th, 2012, 12:50 PM
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There was 2 kinds of Carburetor's used on a 300 I6, a Carter YFA Feedback and a Non-Feedback, look at these two and see which one matches yours:

Feedback:



Non-Feedback:



HTH you!
  #10  
Old April 13th, 2012, 12:50 PM
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Double Post.

Last edited by BigBlue79; April 13th, 2012 at 12:53 PM.


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adoporto , ASwaff400 , BigBlue79 , Booba5185 , Calvin Spiff , catmechanic07 , cmarsengill , cschneid13 , DON CHILDS , i6lover , jhollow10 , JSoko , pegmeister , Ridgerunner , Russo2 , sbellinghausen , William , Zach Willard

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1981 , 49l , black , f150 , idle , rough , smoke

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