Inliners International Forums General Discussion Engines Tuning a motorcraft 2100

I put a 2100 carb on my 292 about a month ago. It has been working pretty good with no bogs or hesitations as installed. The carb is a 1966 off a 289 mustang with #49 jets and unknown power valve. At cold start it fires up well even though no choke is hooked up. The problem I am having is that it seems to be running really rich at idle. The exhaust is really strong and slightly dark when you fire it up and idle. Also when it warms up to 190 it seems to start making a putt putt miss in the exhaust. nothing major but a miss. I order some 46# sized jets last night to try and lean it out a bit, but not sure what to do with the power valve. Any ideas?

Install a wide band 02 sensor and gage - otherwise your guessing.

The AEM one works well and does not require a free air cal which makes it plug and play.

My guess is the power valve is leaking. If you turn the idle mixture screws in all the way and it still runs - the fuel has to coming from somewhere..

A lot of people think wide bands are only for tuning efi systems which is incorrect.

It will help you get the right jets in it for cruise and then drill out the PVCR to correct for WOT. Just do this one drill size at a time as its hard to go smaller.

Try here
http://www.network54.com/Forum/88781/

Best forum on the planet for Autolite carbs.

Somebody may have swapped a booster on that carb, that changes all the air bleed sizes. Common problem if carb has been played with.
Or it could be dirt, etc.

You know, those will run with the lid off so you can check the float level wet. Do it outside though & if youre new to them have a fire bottle handy. I've never had a problem in 40 years, but just in case.

Lid comes off w 4 screws and the aircleaner stud. Then set the lid back on, start it, and take the lid off. You can see the float level, should be about 3/4-13/16 below the top surface.

While the lid is off, you can pull the booster with that one big screw. Don't let any parts drop down (or just pull the carb). CLean the booster in carb cleaner or lacquer thinner, acetone, etc and blow with air a couple times, make sure no holes are plugged.

On the left front mounting foot there should be a number like c6df-a or just 6d-a, that identifies the carb.

On the bottom of the booster there will be a letter stamping.

The carb forum folks will want that info. They are good folks over there.

I've run numerous 4100s (the 4bbl version of the 2100) on the Chevy 6, stock jetting is usually right on if the carb is running right.

Changing the main jet has little affect on the idle A/F ratio - only about 1% per jet size. Look elsewhere as has been suggested.

I love those Autolites - way easier to work on than a 2300 Holley. Good luck.

Here's a set I'm monkying with to replace a 4V: