Rough Idle...

[A_Bartle]

I have a 1976 Ford Maverick and it has a 200 in-line six engine. I purchased it at the beginning of the year, it came from Alabama and it's only got 14,000 miles on it. The car was running very rich and sometimes stalling. I pulled the carburetor (a Carter, model YFA carburetor) and had a mechanic install a carb kit. It ran much better, but was still not quite right. I drove the car to the same mechanic to have him fine tune the carb and check the timing. When I picked the car up, he said that he has worked on many of these I-6 engines and they never run completely "smooth". After the adjustment, the car seems to run well at highway speeds, but it idles a bit rough, and when I come to a stop sign, it almost seems like it's going to stall. I had a couple of friends (who know more about engines than I do) listen to it, and they said that it sounded like it was starving for gas when idling. One guy said that he thought perhaps one of the ports may be partially blocked, and the mechanic may not have cleaned/soaked the carb good enough when installing the carb kit.

1.) First, it is a common characteristic that the straight 6 engines idle a bit rough?
2.) Any suggestions as to what I should be checking for? Could the problem be a sloppy carb kit install?

Thanks for any help you can offer!

[supertechnician]

I would look more twards the fuel tank itself. It is 30 years old and if it only has 14,000 miles in it, then it has obviously sat up a while. You may have a cloged inlet hose in the tank, due to oxidation build up. This is all based on if it has the original tank on it. later

[Davescort97]

Check the idle adjustment screw(s) at the base of the carburator. You screw them in until it is lean enough to make the engine slow down, then you screw them back out 3/4 of a turn.

[denisond3]

I had an ohv six in the 52 Ford F1 that I drove for ten years, and for the entire time it idled poorly. The hotter the engine was, the worse it idled. I tried all the usual schemes (except doing a valve job), never did get it to idle smooth. But on the highway it ran silky smooth, had a broad torque curve - and was happy doing 90 mph.
I also had a 52 Ford pickup with the flathead V8. It idled silky smooth, but had weak low end torque, there was vibration above the idle (feeble counterweighting on the crank) and at 60 it felt like you were flogging it.

I would do a compression check on it while warm, see if the values are pretty even. From being that old, with that little use, there might be a lot of rust on the valve mating surfaces.