Thread: Carb upgrade..

  1. #1

    Carb upgrade..

    I just ordered a Motorcraft 2100 to replace the POS Carters on the CJ. (81 CJ7 258 Auto) Anyone had experiace in changing the carbs out? If so, is there anything I need to watch out for or that was difficult for you? This is my only means of transportation, and I am not a mechanic. Dont want to be left high and dry but the carters is starting to idle rough after long drive times.

  2. Re: Carb upgrade..

    Did the swap to my 81 cj7 manual 3 months ago. as long as u have the adapter plate and the person set up the carb right it will go smooth. It really woke up my 258 too. idles great and excellent accel. you'll be happy

  3. #3

    Re: Carb upgrade..

    I have a mc2100 on mine. It's a 1.08 with 48 jets, and it runs way too lean. My spark plugs are white.

    I'll also say that getting the carb and its adaptor to seal perfectly is a pain. I've taken the carb off at least 8 times, re-sealed everything, cut new gaskets, and I still have a leak... just in a different spot. I'm thinking a Clifford intake would solve those problems.

    If my Jeep didn't have the mc2100 on it when I got it, I would have kept the Carter until I saved up enough to buy a Clifford intake with a Holley or something.

  4. Re: Carb upgrade..

    MC2100 is the best thing i ever did to my 258! get the adapter plate, rebuild your mc2100 and install. I did a little linkage adaptation since the carter and the MC hook up differently.

  5. #5

    Re: Carb upgrade..

    you need to work the linkage a bit but it was easy to do. i just used a l bracket that was in the drawer to change the angle from rear pull to down pull and put a pivot pc on the end. everything worked the 1st time out so i say go for it and you'll never look back to the carter again.
    Willy Mudd.slinger Fosbinder

  6. #6

    Re: Carb upgrade..

    oh yeah, i used the original ford 1/4 inch thick gasket and had no sealing probs.
    Willy Mudd.slinger Fosbinder

  7. #7
    Join Date
    Jun 2006
    Location
    London, England
    Posts
    23

    Re: Carb upgrade..

    Iwent with the Webber, easy replacement, everything came with the kit and it's basically set up except for a tweek on the idle screw

    Stew

  8. #8

    Re: Carb upgrade..

    I haven't messed with the motorcraft carbs. I run a holley 4 barrel on my 258,but I did have the same issue with rough idle after long drives. It turned out to be multiple vacume leaks. One being the vacume line for the break booster was leaking at the magnifold and several intake bolts were slightly loose. A new fitting for the vacume line and re torqueing the magnifold bolts had her purring like a kitten. So don't rule out vacume leaks if the new carb doesn't fix the problem.

  9. Re: Carb upgrade..

    i put a 2150 on mine 9months ago and never looked back,you'll be happy with it one question though if you went to the trouble to order it why not order the 2150 thats the upgraded 2100 and very sweet,

  10. Re: Carb upgrade..

    Quote Originally Posted by sptrmike View Post
    i put a 2150 on mine 9months ago and never looked back,you'll be happy with it one question though if you went to the trouble to order it why not order the 2150 thats the upgraded 2100 and very sweet,
    Hey...I bought a 2150 off of eBay a while back and am trying to fit it on a '84 258. Problem is the adapter plate doesn't match with the bottom of the carb. One entire section is wide open. I can't imagine it is supposed to look this way. Another issue is the clearance on the power valve cover screws. If I double the gasket, it clears. Any insight on this?
    Attached Thumbnails Attached Thumbnails Carb upgrade..-2150_a.jpg  

    Attached Images Attached Images Carb upgrade..-2150_b.jpg 

  11. #11

    Re: Carb upgrade..

    Quote Originally Posted by cuba_pete View Post
    Hey...I bought a 2150 off of eBay a while back and am trying to fit it on a '84 258. Problem is the adapter plate doesn't match with the bottom of the carb. One entire section is wide open. I can't imagine it is supposed to look this way. Another issue is the clearance on the power valve cover screws. If I double the gasket, it clears. Any insight on this?
    You must use a gasket made for the carb, not the adapter. I think there is usually a big, 1/4 in. thick, rubber/cork/whatever gasket that is between the 2100/2150 and a V8 manifold. If you find one, use it; it clears those powervalve screws. If you just use a regular 2100/2150 gasket, then you must grind down two spots on the adapter so the carb sits flush.

    Also, you might have noticed how much smaller the inlet on the manifold is than your new adapter. I took the 3/4 in. plastic spacer off the manifold (the stock one that is blackish gray), "port matched " that to the adapter while keeping the bottom of that plastic spacer the same, and stuck it back on. The idea is efficiency, but I doubt it did much. It looks cool, though.

    Out of curiosity, what size 2150 did you get?

  12. Re: Carb upgrade..

    Quote Originally Posted by Collin the Hen View Post
    ...Out of curiosity, what size 2150 did you get?
    Unfortunately, I think, I got the 2150a. Apparently this was for the Bronco II and has the feedback circuit with the electric solenoid. I may have bought more headaches for myself by getting that carb. I am confident I will figure out a way to get it functioning correctly and still be tons better than the Carter.

  13. #13

    Re: Carb upgrade..

    Quote Originally Posted by cuba_pete View Post
    Unfortunately, I think, I got the 2150a. Apparently this was for the Bronco II and has the feedback circuit with the electric solenoid. I may have bought more headaches for myself by getting that carb. I am confident I will figure out a way to get it functioning correctly and still be tons better than the Carter.
    Hmm... haven't researched that one. Maybe you can strip off all the electrical junk and have a straight up carb?
    I think the biggest concern is the jet and venturi size. Make sure it'll run rich enough for you engine. I posted this before, but 1.08 venturi size, and 48 jets is way too lean for my engine.

  14. #14

    Re: Carb upgrade..

    you can probably convert it back to a normal carb. just make sure and keep some kind of choke system on it since you are up in the cold winter areas. here in south texas a person can run with no chokes but virginia, no way. it gets really cold there
    no more jeeps at this time. next time it will be a cj with a v8

  15. Re: Carb upgrade..

    Well, I am headed to Washington state, so it will definintely have the choke. It's already set for cold weather now. I think I will run it with the bleed open for now, and then re-adjust with it blocked off and see which way yields a better power/mileage trade-off.

    The intake for the bleed is under the air cleaner, so that is the easiest place to block it off. What I really need to know and have yet to find on the internet is what circuit the bleed feeds into. I am assuming it is the high speed or WOT circuit since its original purpose was to add oxygen to the exhaust for emissions control. I cannot tell just by looking and don't know enough about carbs "yet" to figure it out.

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