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I have a recently purchased 1981 F-150 4x4, with a 351m carburetted engine. It runs beautifully, never over-rich, never stumbles/misses, pulla great vacuum, and has perfect acceleration without hesitation. The only problem I do have is starting it when it's cold. It's as if the fast idle isn't taking hold at all. The choke works fine, or it would miss/backfire, or just plain not start. It'll run just fine if I babysit it, and hold the gas down to keep the revs up, but it goes through an incredible amount of fuel starting it this way. The engine is non-emmisions(Canadian truck). I was wondering which step to set the fast idle screw to, so that this works properly. I can't seem to find the correct information in my Haynes manual.
If the timing is to far advanced it would be the problem, i just had to reset the timing one my flareside and my dad told me not to set it to far advanced, although it would run nicer, but it would be a pain to start. If you have a timing gun it only takes about 5 minutes to check. As far as the idle screws i can't remember which one either.
This isn't a timing issue at all, or it would be hard to start hot, if to far advanced. Once warmed up it starts at the turn of a key. I'm looking for the proper fast idle setting only, as everything else is in proper working order. I just don't want to have to sit in the truck and babysit it until it's warm for the winter months. It's kind of nice to be able to start it, lock the doors, and go back inside while it warms up.
It idles at a nice steady 850rpm in gear(automatic) and around 950 in neutral/park. Took it for it's first highway cruise today, and it seems to have cleared it's throat a bit. Will look at getting a can of carb cleaner, and then see what happens. It seems to do pretty decent in the mileage department, and acceleration, and maintaining speed are no problem at all.
It went up to that today after the highway run, thus bringing me to the conclusion a can of carb cleaner is in need. This truck pretty much sat for the summer, and maybe a bit longer. A buddy of mine bought it, but it needed to many repairs for him, so I bought it. Most of the repairs are done, but this is the only real glitch I've run into. After the carb clean I will re-adjust idle, and see about setting up the fast idle cam properly. It may simply be sticking at this point.