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[travisneville]

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.

 

[DonsBolt]

I don't know a lot about the Autolite carbs, as i am more of a holley guy

Though a few things you can do with any carbs that you run off road

lower the fuel level in the bowl
get a adjustable fuel pressure regulator, and tun down the psi to about 4 psi

Both of those will help reduce the loading up

When you get back on the street raise the fuel level to normal, and adjust the regulator back to 6 psi

 

[broncnaz]

No spring loaded needle seats for the motorcraft carbs as Donsbolt said lower your float level.
My experiance with spring loaded needle seats is they tend to be more problematic and not really worth the price unless your doing some high speed rough stuff then they would be benifical but in the slow stuff standard needle seats are fine.

 

[Buldozer]

lower the fuel level in the bowl

Does this work equally well with the Holley's? I have the same problem with my 650.

 

[oleguy74]

4160's 470ta,570ta,650 ta's dont have spring loaded needles but have spring loaded floats.

 

[broncnaz]

Does this work equally well with the Holley's? I have the same problem with my 650.

Yes and with a holley its very easy to adjust. I run my floats lower than specs call for I lower it the point that I really have to shake my bronco to get the fuel to slosh out the fuel bowl sight plug hole and make sure I can still drive at hiway speed. If your 650 is a double pumper you probably have center hung fuel bowls which are not the best for offroading especailly the up/down hill stuff but you can install vent whistles that will also help. See my holley carb tips article to the left it will apply to your carb as well.

 

[Buldozer]

See my holley carb tips article to the left it will apply to your carb as well.

Took my new frame off project out for some hill climbing yesterday and almost had a disaster! Accidentally got over the edge of a very steep hill (navigator error, apparently 5 diamonds looks just like 2 when you are looking at concrete hill... if you are my wife) ...anyway once you are headed strait down might as well go for it i figure, so I am doing pretty good and all of a sudden the engine really floods and I am doing a right front wheel stand! I am headed over quick with a project I just worked 6 months on!! :-[ With thee wheels in the air and ground coming fast I hit the front locker switch and when the ARB turned loose the other three wheels came back to earth and about that time the engine caught fire and the down the rest of the hill we go a lot faster than desired (thank god for hydaboost) but on all four anyway. Near disaster averted, but certainly got me to focus on the carb flooding issue!

broncnaz I had your mod page up and was working on that vent tube when you posted this. I already had the bowl levels well below "slosh out" but I may go even a little lower...and I was thinking about cutting my fuel pressure to 1 - 2 psi off road (what do you think about that? I see several other carb types recommend a very low fuel pressure so when the needle bounces you don't get so much bypass into the bowl at once).

Oh and other than this and a blown out auxiliary air tank supply line (too close to the header), my new rig preformed flawless!

 

[Buldozer]

Oh I forgot to add that I had already installed whistles when I built the carb.

 

[broncnaz]

Lowering the pressure can help but those center hung bowls are not the best for hills. One other trick that worked for me when I had brass floats and one decided to fill with gas is a electric fuel pump with a switch so you can turn it on/off at will. Helped me get to level ground and figure out that my float had sprung a leak luckily it was in the secondarys and I just adjusted the needle seat until it was closed. Got me through the rest of the day and home with no other problems

 

[travisneville]

my bronco is offroad only any suggestions on the float level or just give it a little bend and try it. thanks for all the help.

 

[broncnaz]

Just bend it lower and make sure it still runs at your needed top speed. Kind of a pain with the 2100 but once you get it set where you want it it should be good to go.

 

[bludorbronc]

One other thing for 4 barrels is to attach a single piece of hose onto both front and rear vent tubes in an arch so any over flow from the vent tubes runs into the opposite bowl and not into the motor and make sure you cut a hole into the hose at the top of the arch for venting. This will help alot. Make sure that the hole is not sealed against the air cleaner.

 

[haydenjsle]

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.