Ford 4x4

Hey guys my 85 f-150 with the 4.9 is running pretty rich lately, I figured I would just go and lean her out a bit, I found the idle screw and the lean/rich screw on the carb. Which way do I turn the screw to lean her out? Is there only the 2 screws on the carb or are there more? Thanks guys!

jumpingjoeusa

Turning the lean rich screw clockwise will lean the carburetor air fuel mixture

Ford 4x4

Okay, what if she is still running rich afterwards? It does have some older gas in it so maybe that would be why it seems to run richer too.

97' 4.6

A carb generally doesn't just richen itself up, if you haven't played with the carb then its most likely not running rich. Pull a few plugs and look for a light/medium mocha brown color, thats what you want them to look like. If the plugs look darker, like a dark tan/brown, your running rich (and obviously if the plugs are fuel soaked your way rich). Clockwise on the air/fuel ratio screw with lean the mixture, generally its best to rotate 1/8" turn at a time.

Ford 4x4

Okay, I will check all that out this weekend. I can kneel down behind the exhaust and smell strong exhaust fumes. It will sting your eyes once in awhile also, so im thinking she is rich.

Matthew Burr

that is probably the feedback carb... you should look up some info on it, but if there is a sensor out of whack then the computer wont adjust the mixture and you will run rich. so check the map sensor on the passenger side wall and the O2 sensor on the exhaust manifold and the tps on the throttle plate. otherwise, how does it idle? rough or otherwise smooth?

Ford 4x4

She use to run like a top, but now she is rough, sounds like it has a cam in it lol

would I pick up any codes from the computer if the sensor was bad?

jumpingjoeusa

I had the same problem and I didn't change the carburetor adjustments. Instead I removed the module off the distributor and cleaned the back of it and the surface of the distributor where it mounts. Applied dielectric grease and installed. Back to smooth. To remove the module you need to purchase a tool to remove the module. The tool is pretty cheap a Advance auto parts. This is the very first thing I would do as weather affects the module over time and it must have good contact to operate properly. This affected my timing causing my engine to run rich. If it ran good before I would not go about adjusting things.
Good Luck...

jumpingjoeusa

The module is mounted on the outside of the distributor so it easily removed 2 screws and 2 electrical connections.

Matthew Burr

Has it gotten hot recently? A blown head gasket can cause the rich smell and the rough idle. Check ur spark plugs, do any have what looks like coral growing on em? U can take it to get tested as well, but if you take the cap off ur radiator before you start it and coolant keeps getting pushed out while its running thats a good indicator too.