81 4.9 ford stepside idle problem
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81 4.9 ford stepside idle problem
ok so i recently got a 1981 stepside with the 4.9 inline 6. when i got the truck it ran good untill i got to 70 mph and then it would spit and sputter like it wasnt getting fuel and over time it eventually got to the point were i could barely do 30mph. so one day i stalled on the side of the road and took the fuel filter out that is in between the carb and the fuel pick up and went to blow in it and it was barely letting anything thru so at the time i needed to be somewere so i just poked a hole thru the filter with a screwdriver. it ran good and went over 70mph for alil but the same day it started to load up alot at idle to the point that it flooded itself out i know this because the carb would start leaking gas and it would miss and shoot black smoke when i floored it. so i thot ok its flooding itself out because to much fuel is getting passed the filter so i bought a new one and put it on. turns out i was wrong. and i still cant find the problem. any help would be helpfull.
Laughing Gas
Joined: Nov 2010
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From: Johns Creek GA
It's possible that some crud from the gas tank got through after you poked a hole in the filter, and it's keeping a needle valve from seating correctly. The tanks on these old trucks are often full of rust and such - I just recently had to replace mine.
You're probably going to need to open the carb up and clean it good - a combination of compressed air (make sure not to blow away any small parts!) and carb cleaner should do the trick. And then you'll want to think about cleaning that gas tank out - if your filter was plugged up that badly, it's a good sign the tank is going bad.
You're probably going to need to open the carb up and clean it good - a combination of compressed air (make sure not to blow away any small parts!) and carb cleaner should do the trick. And then you'll want to think about cleaning that gas tank out - if your filter was plugged up that badly, it's a good sign the tank is going bad.
Fleet Mechanic
Joined: Jul 2011
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Poking a hole in the filter and sticking it back on like that was a mistake. It would've been way better if you could've just put a new fuel filter on it and had you done so, it probably wouldn't be where it is now. But hey, we all learn, so no big deal. It should be a simple fix if it's the problem I'm thinking of.
On a Carter YFA, when gunk gets up into the fuel bowl, it goes through the needle and seat. And, when enough builds up, will gum up the needle and seat causing it to run pig rich or flood.
It sounds to me like you need to 1) take the air horn off the carburetor and spray out the fuel bowl with some carburetor cleaner multiple times (making sure to get down into the needle/seat), 2) put in a new fuel filter, and 3) if it's bad enough you'll need to get a rebuild for the carburetor and rebuild it. Thankfully, rebuild kits don't cost hardly anything, and the YFA is a very easy carburetor to learn on.
There are rebuild videos on Youtube of Carter YFA carburetors.
Good luck, and welcome to the forum.
On a Carter YFA, when gunk gets up into the fuel bowl, it goes through the needle and seat. And, when enough builds up, will gum up the needle and seat causing it to run pig rich or flood.
It sounds to me like you need to 1) take the air horn off the carburetor and spray out the fuel bowl with some carburetor cleaner multiple times (making sure to get down into the needle/seat), 2) put in a new fuel filter, and 3) if it's bad enough you'll need to get a rebuild for the carburetor and rebuild it. Thankfully, rebuild kits don't cost hardly anything, and the YFA is a very easy carburetor to learn on.
There are rebuild videos on Youtube of Carter YFA carburetors.
Good luck, and welcome to the forum.
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well i just got done tearing it apart and there was a bit of sediment in the bowl so i cleaned it and put it back on and its still runnin abit rough so i advanced the timing and idle screw on the carb and it seems to be allright. there is a little bit of a miss but i can deal with that as long as it dont load up again. i will be giving it a good tune up here not to long tho so hopefully the slight miss might be a plug or something minor
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