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Autolite 4100 kickdown linkage - can I add it?

12K views 46 replies 6 participants last post by  chrlsful 
#1 ·
So I purchased an Autolite 4100 and did a rebuild on it. I am planning on replacing the current Motorcraft 2150, which is sitting on the Edelbrock Performer (There is a 1 '' thick reducer plate currently on the intake, which centered the carb). The current 4100 does not have the kickdown rod attachment on it. The 2150 does, I have attached photos.

So my question: Does anyone have a 4100 with the Kickdown linkage, and can I add it to the 4100 I have? I can tear the bottom half down still to add it. Has anyone done this?

Will the 2150 linkage fit on the 4100? The basic rod/throttle linkage is close, but not the same. I am assuming the same stop for my Dashpot would engage the adjustment screw on the kickdown linkage. I actually took the dashpot and put it on the 2150, and it lines up pretty close.

Thanks for any answers in advance!

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#3 · (Edited)
if the downshifr bracket is a tight fit, get that angle grinder out. Or maybe attach it to the outside of the throttle bracket?

OP, such a clean carb! Here is mine
 

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#11 · (Edited)
To a small bracket attached to the intake. It seems to be a bubba job, funny, this guy had a shop that did most of the work, I have a ton of receipts, but they did crap work. Everything seems to be jacked up or a little off on all the extra work they added.
 
#15 ·
My vehicle does not have the original drive train in it. It has a D1ZM-6015-AA Ford 302 block from 1971, and a D4AP-7006-AA 3-speed FMX Transmission from 1974. So it has the newer rod style linkage, sorry, i should have been more clear.
 
#17 ·
Went to Rod's Carburetors in Phoenix, they were super helpful. Pulled the throttle rod from another 4100 with the kickdown linkage. It is virtually identical to the rod and linkage on my 2150. Just as an FYI. I got a few other small parts, and out the door for $25. I will post as soon as i get it cleaned up and installed. Thanks everyone for the help.
 
#18 ·
hope you got new screws,also note that the throttle plates have an up, and down side. once the plates are in, back off the idle speed screw and tap the plates with a screwdriver handle to settle them in the bore before tightening the screws. then stake the screws so your engine doesn't swallow one
 
#22 ·
Well, we are done. I am amazed at the throttle response and new acceleration with the 4-bbl carb. Now getting to this point was a serious pain in the ass. As I said above, I have never delved into doing a carb adjustment or rebuild. This was quite an experience. I will start at the top.

So we got the carb on, I am using a snythetic 1" spacer with a PCV nipple on the rear. I used the gaskets that came with it. MISTAKE. We fired up the carb, and it was running super lean, and could not get it adjusted, so we suspected vacuum leak. We had one at the very front. Used the Carb Cleaner and Water tricks to diagnose. Fortunately my neighbor works on his own cars and boats, and has a lot of experience with Carburetors. So we pulled the carb, (#1), did some checking on the leveling of the carb, the spacer, and the intake. No issues there. Put it back on, same issue. (#2, #3 removals) We ended up using the gaskets out of the rebuild kit (More on the $#%#$%# Rebuild Kit in a minute). Once we got the gaskets fitted, used a bit of grease as a helper, the carb had no more leak. Still have a little bit of a leak at the new throttle rod, which has a little bit of play but can live with it.

Still having problems with the adjustment once we get this fixed, seems there is a lot of play in the choke arm going to the pump diaphragm. So working on that. Then we realize I have the choke spring set up backwards when I put it back together. I should have studied the 200+ photos better. So remove carb (#4), spend about an hour finally getting it right (took it on and off 4-5 times), and also find I have not peened the pump cover very flat, and there was a leak there as well. Take it apart, flatten it well, and put it back on.

Sometime during this process, I must have allowed the check ball from the pump to dislodge, and it was not in place. So fuel dumping again. Take carb off again (#5), fix this, put back on. Mind you we are in 106 degree heat in Arizona, so not as much fun.

Now we start working on adjustment, and we are all of a sudden way too rich. I mean dumping black smoke. So we open up the carb, and the primary bowl is full to the top. The float needle will not close all the way. The secondary is fine, but the primary will not close, no matter what the adjustment. So I use the old needle and seat, which on this antique is a check ball assembly. Fixed.

Put Carb back on, and still too rich, I mean no way we can adjust. Take the top off, and now we can watch the primary bowl draining when ignition is off. What the hell? We take the carb off (#6), check for leaks, cracks, nothing. Put it back on. Same issue. I take the Power / Economizer Valve off, and i have two gaskets. WTF? Thats on me. We put it back on, put the carb back on, same problem. Take the carb off (#7), and find the Power / Economizer valve is leaking like crazy. The whole assembly is full of fuel. So the diaphragm is toast.

Go to O'Reillys, get a new Power / Economizer valve, a 6.5, since the one in the kit was a 5.5, and buttoned it up . Put everything back together, and fired it up. Did the Idle mixture to about 2 1/2, got the idle and fast idle adjusted. It still has a bit of a rough idle, but holy cow, I am super happy with the new power this vehicle now has. With only a 302 in it, it does have some giddy up, way more than before, especially with the kickdown and throttle linkage binding up being fixed. .
 
#25 ·
So I have some seriously rough idle now. Misfiring? I am going to change spark plugs and wires this week. Never had it before. Lot of vibration coming from the engine. Would I need to adjust the timing with a new Carb? Once I get rolling, I seem to have good engine response. But put it in Reverse, I can barely keep the engine running.
 
#27 ·
Yes, we were working on that. Idle mix seems to be right, we have the mixture screws at about 2 1/2. Question, would the Power valve size make a huge difference? I have a 6.5 on it now, but some places I looked up say it should be higher.
 
#30 ·
I needed two gaskets on my PC. If you go out in the morning and the bowl is empty you will need two of them also.
Does not seem like that is your issue though.
 
#31 ·
So, I am having a lot of trouble getting this carb tuned, the idle is high, and I have low vaccum. When I bring the idle down, it stalls. It is a 4100 with 1.12 venturi. What size jets would be recommended? I think it has 52/54 primaries on it now, I will have to double check. Would new/different jets make a difference here?
 
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