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post #8 of (permalink) Old 06-29-2009, 03:56 PM
I Might Just Know What I'm Talking About
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Join Date: May 2002
Location: Selma,CA in the middle of the vineyards, Central California
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I got a ton of stuff saved on the computer for the MC 2100, way too much to post up but are few items that might help that haven't been mentioned yet. Oh yea, most of my problems usually lead back to a vac leak. As for Jet size, use Rich's Propane trick.

It sounds like you are almost there with your MC2100 carb my friend. OK, here is how you tune an MC2100. Please note that you will need to do all of these steps in order without leaving any of the steps out. Trust me on this, I've completely tuned MC2100s before, only to end with a carb that was running like caca, all because I forgot to do something simple, like check the pump pressure. OK, here are the steps:
1) Check the fuel pump pressure. MC2100s like 4 to 5 PSI, no more and no less. Do this step first and don't skip it! Your carb cannot be properly tuned if the pressure is below 4 PSI or above 5 PSI.
2) Float level. You need to adjust the float dry. It's much simpler to remove the carb and turn it upside-down above your head to do this. Measure 1/8" from the end of the float and place a mark there. This is the spot where you will measure the height from. Next, turn carb upside-don as previously stated and measure the distance from the mark on the float to the fuel bowl flange. It should be 9/16" maximum. 1/2" is generally OK, but it is better if you can set the float to EXACTLY 9/16". If it is more than 9/16" the carb will want to run like poo.
3) Idle mixture: Warm engine to normal operating temp and set the curb idle RPM to around 650 RPMs for a standard tranny equipped Jeep. Using a vacuum gauge that is hooked to a manifold vacuum source, turn each idle adjustment screw gently 1/4 turn inwards until the engine starts to stumble and run rough. Back off each screw in 1/8 turn increments until the engine start idling smoothly again. It is important that you turn both idle screws equal amounts. If you have turned both screws equal amounts and then you turn one screw slightly and the engine starts to stumble, back off the screw to it's pre-stumble position and leave both screws alone. This is the best lean position. Try this and post the results.
Your MC2100 lovin' friend;

Mc 2100 & 2150

AMERICAN MOTORS (8 cyl) ............... ........... 1968-79
EDSEL (8 cyl) .................................................. 1959-60
FORD / MERCURY (6,8 cyl ) ............... ............ 1958-86
FORD TRUCK (6,8 cyl) ...................... ............. 1963-86
JEEP (8 cyl) .................................................. ... 1971-92
LINCOLN (6,8 cyl) ............................... ............ 1977-83

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The Ford/Autolite 2100 was first introduced in 1957 and was installed on applications till 1974, In 1975 it was revised to become the 2150 and were phased out in the mid 80's.
The number on the side in the circle is the venturi size, Ford made 8 differing venturi sizes of the 2100/2150 depending upon the applications used. Since this was the ONLY FORD two barrel carburetor used from 1957-the early 70's Ford installed it on MANY differing applications. As you have noted even AMC bought this carb from ford for its applications. The venturi sizes ranged from .98, 1.01, 1.02, 1.08, 1.14, 1.21, 1.23, and the hard to find 1.33
The 2100 is very easy to tell apart from the 2150 as the 2150 is labeled Motorcraft on the carb top and has a choke vacuum break extending from the rear of the carburetor. You can also tell the later 2100's (70's versions) by the "raised" float bowl section and the choke unloader located just aft of the choke flap. (sometimes not used in the earlier 70's models).
OF course all 2100/2150's will have the part numbers stamped on the drivers side front foot which will tell the applications and year of manufacturer.
The earlier 2100's are probably more desirable as they’re are simpler carbs and were not tuned with economy in mind as are the later ones. Consequently the later ones tend to run a bit leaner and are often more temperamental, plus often have extra vacuum accessories.
The 2100/2150 carburetor has been reputed to be the BEST CARBURETOR series ever built. The 2100's are basically two barrel versions of the famed 4100 4 barrel carburetor and many parts are compatible.
Any other questions about 2100/2150's feel free to write me
Bill White, White Automotive


"The Heep" 73 Commando, 258 I-6, T-18, Scout Dana 300 w/Tera 4:1 Kit, SOA, PS, Thru-dash Cage, Alcans, OBA, ARB's, HEI, Ft disc, MC 2100,Dents, Mud & Rust.
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