i need help finding out more about a spring loaded needle and seat. i have a 2100 carb and was wandering where to get one those springs for the float that is supposed to help with the sloshing fuel. my bronco is for offroad only and tends to load up on the rockier trails and hillclimbs. thanks for any help or comments.
Send me a PM if your still interested --I have a couple of these --its a small spring that sits on the float pin to help dampen float movement. Send me a PM. Unless you're getting on the throttle real heavy on obstacles (bouncing) or flying down a rocky trail, you're not going to benefit much from this. When I ran the MC 2100 here are some of things I did to help from loading up on steep obstacles and higher elevations:
1. install adjustable fuel regulator as mentioned above--I used to run mine down to 2 psi on high mtn. trails sometimes
2. lower float level as mentioned above--if it is offroad only you can get away with even slightly lower than if it was street & trail/ I would occasionally run out of gas in my bowls on long steep climbs in the mtns.
3. rejet in small increments-you don't want your engine running too lean
4. install later opening power valve or 2-stage power valve--this seemed to help me alot/ you'll have to change the power valve cover if installing the 2 stage power valve/ I think the power valves might even interchange with the holleys
5. check the size of your carburetor if it is not the stock Bronco--IIRC there were 3 different sizes of the 2100/ the venturi size is stamped on the driver's side of the float bowl (do a search on how the venture size correlates to CFM)
With a little trial and error on all of these I managed to get my MC 2100 to run decent---about the same as all the holleys I had, but not better than the quadrajet that I eventually went to. Converting to fuel injection turned out to be the curall for me. Good luck.