I just did the Motorcraft 2100 1.08 venturi carburator swap on my 1990 Jeep Wrangler. The Nutter bypass was performed on this jeep by myself about 3 months ago.

My question is: there is a flat spot when accelerating. It is at about 1/4 throttle. Is this normal? It idles normal and performs 200% better than the stock Carter carburator except for the flat spot. Anyone ever had this problem or know a fix for it?

On a side note, I just installed a Weber Carburator on my freinds 1990 wrangler that I just got done rebuilding after an engine fire and did the Nutter bypass. I wish I had $500 for a Weber. It is flawless.

i had the exact same problem. i still am to some extent. it used to be so bad that i could barely accelerate at all. the problem was my timing. i has been setting it at 1600rpm per the instructions on the emissions lablel. it should be set at 650rpm. i set mine to 9 degrees advanced and it runs great, but still has a slight stumble. i will advance it a little more shortly. good luck

What X89 said.. Also check the advance with a light! while slowly advancing the rpm watch the advance to see when the vac advance and then the Mechanical advance comes in.. then drive it and see where the flat spot is in rpm..
By doing this you should be able to surmise what changes in the mech advance are needed.
If the carb is in good health I doubt the carb is the problem. Flat spots when FLOORING the pecal are from not enough fuel in the pump system this is changable with the linkage on that carb.
I put my dist vac on a constant source and enjoy better ideling. You may try this to see what happens.
Just a guess but I'd betcha your mech advance is coming in a bit late..
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />

You guys are awsome. That is exactly what it was. The vaccum port that I hooked my Vaccum advance up to was not pulling any vaccum.