View Full Version : Autolite 4100

01-05-2012, 07:33 PM
Hey guys. I just bought a 1959 t-bird in rough condition (it was sitting for about 30 years) and have a question about the carb. I have been working on the one that came with the car but it's starting to become a headache to get it to move and function freely. The secondary throttle shaft isn't moving and seems to be stuck..I've let it sit off and on in penetrating oil and nothing...the rest of the carb is cleaning up and moving nicely after all the treatment.

Should I drop the cash to just buy a another carb off of craigslist or eBay? Let me know what you guys think

Thanks for reading my first post.


01-05-2012, 09:53 PM
Hello David - you found the right place to be for your questions on your "new" Squarebird. There are lots of knowledgeable folks on this site to help. I know I've learned a great deal here.

I just rebuilt my 4100 carb on my 1960 Tbird over the Christmas holiday - I'm guessing they should be the same carb. I used a Walker kit from O'Riley (Part # 15255) however it does not include the secondary diaphragm pump or rod which I bought form NAPA (CRB 24241). The kit also does not include new main jets (which I took out and cleaned) - only float seats and needles but has the power valve and primary diaphragm . About $20 for the carb kit and $7 for the secondary diaphragm and rod.

The secondaries are vacuum operated - mine won't open under full throttle while the car is sitting - has to be under load while driving. There is a plastic rod that should stick out of a cam on the side of the carb to close the secondaries and will hold them closed unless the primaries are open. Mine had been broken so I installed a small screw with a nut in the hole where the plastic rod should be.

All in all it's a great carb - the fuel filter is specific to this carb - see this post http://www.squarebirds.org/vbulletin/showthread.php?t=12268
You'll need to take the carb completely apart to get all the passages cleaned out like under the main jets - mine was full of old gas deposits there and I also ran a small wire through all the air and fuel passages to be sure they were all clear. Took about half a day to rebuild it but now the car runs much better - completely different. It's probably a good idea to rebuild it if it has been more than 10 years as today's gas now has ethanol that will eat the end of the old rubber needle tips. The new needles are "supposed" to made of vitton rubber which can be used with ethanol. Yours may still have the brass needle? maybe those would be keepers.

If you change the carb you'll need to be sure the air filter housing will fit the new carb unless you also buy an aftermarket style filter - guess that depends on how original you want the car. The choke on the 4100 is de-activated by heat from a heat tube via the exhaust manifold on the passenger side and many of the replacements are electric so you'll need to run a hot wire to the new carb if you replace it. I'm sure there are just about as many folks who have a replacement on their car as have kept the 4100 - form what I have seen - the cost for a good rebuilt 4100 and a replacement carb are about the same but the 4100 kits were rather cheap - not loosing much if it doesn't help. The service manual has a pretty good guide to rebuild and tune the carb.

Good luck either way you decide to go - wanted mine to look original with the original air filter so that's why I chose to rebuild plus my carb is original to the car - my Dad bought the car new......

Let us know how it goes.

Thunderbird registry #5347

Jimz Bird
01-05-2012, 10:30 PM
Here is what a rebuilt 4100 goes for:
http://www.ebay.com/itm/Autolite-4100-1-12-Carburetor-restored-Pony-Carbs-/250296937400?pt=Vintage_Car_Truck_Parts_Accessorie s&vxp=mtr&hash=item3a46dc2bb8#ht_1524wt_698

It may be worth the trouble to rebuild it yourself.:D

01-06-2012, 12:24 AM

Thanks for the responses! I got a few tips for rebuilding and what to get from this! I was looking into rebuild kits and also looking at my new shop manual (got it from my dad for Christmas).

I didn't know that about the secondary...oops. Haha. I honestly think I might have messed that up. It's my first time working on a carburetor.

Do you guys think my filter will fit this? I DO want to keep the car as close to original as possible.



Seriously, thank you for the knowledgable replies!


01-06-2012, 05:46 AM
The best info on the 4100 can be found here http://www.network54.com/Forum/88781/ Search for threads a couple of years old that Bill White gave answers to, he knows them better than anyone. Original cars are cool JMO Bob C

Jimz Bird
01-06-2012, 10:11 AM
Check out that forum and here might be a good 10 bucks to spend:

They take PayPal and you get instant download of a pdf.

I am considering the 1.08 for my Y upgrade.

01-06-2012, 11:17 AM
What filter are you talking about. The '59 carb didn't have an inline filter. There was one in the fuel pump. Only the '60 carb had an inline filter. Those carbs that you looked at on ebay have a different choke on them. The heat tube that goes to the exhaust manifold is at a different angle. Other than that they are pretty much identical with a '59. The frozen secondary is a common problem. It's just a matter of soaking it in penetrating oil and tapping it lightly to try and free it up. I've spent many hours doing it.

01-11-2012, 03:42 PM
I'm not sure..that's what DKheld said about the air filter housing. I ended up going with the carb off of Ebay and it's on the way to my house.


I couldn't get the secondary to move so I gave up on it...Maybe I'll give it another go later on. But for now I have that one on the way.

What do you guys think about it? I was talking to the seller and he said that the only thing that would need to be converted is the choke housing. Is this true?

Thank you for your feedback..I'm still learning a lot about this car.

01-11-2012, 08:14 PM
If you're talking about the air cleaner it will fit fine. The only difference is this carb has a vacuum port that went to the later style air cleaner. You'll just need to plug it. It looks like a nice clean carb. You can change the choke housing if you want but it is easier just to bend the choke heater tube to match the new choke or just fabricate a new tube. I think I used brake line to make a new tube on mine.

01-12-2012, 12:38 PM

x2 on jopizz's comments !!

If you have the original air filter the choke on this carb may hit it but jopizz may have better info on that than I do. The choke appears to stick out further on this carb than on the original style - I know it's all pretty close in that area. If it will fit I like the idea of just plumbing in a new heat tube - easier than changing the choke assembly and getting it adjusted.

On the Autolite 4100's installed on the '60 Tbird's the fuel filter is screwed into the carb body. As far as I know it was a one year only deal. You can replace the special filter with a general purpose one by screwing a hose barb into the carb. Sometimes its a bit hard to get sealed though because the carb and filter have a beveled seal.

I just got mine rebuilt, installed and adjusted. I'll try to get a pic this evening and post it.

I do see the extra vac port on this carb and as jopizz mentions - just plug it or heck - that's the perfect place to hook up a PCV system.

Let us know how it works out - had actually seen those carbs and considered buying one if my rebuild didn't work - nice looking rebuilds.

registry 5347

01-12-2012, 07:46 PM
Here's a pic of the choke assembly with the filter housing on - you can see it's fairly close but there is some room.

The rebuilt 4100 carb.....
2 1/2 inches from the edge of the carb to the edge of the choke housing and about 3 1/4 inches from the edge of the filter housing to where the housing drops down - so about 1 1/4 inches to play with.



and here is the fuel filter set-up I was talking about on a 1960 with the 352 and Ford Autolite 4100 carb.


Hope that new carb works.


01-13-2012, 06:02 PM

Thank you for the photos! You have gone above and beyond with your posts. That helps me a lot when I get this thing bolted on.

Now, here are photos of the carb I got in the mail. I noticed a few differences.








01-13-2012, 06:24 PM
That one looks nice, there's a number stamped in the left/front foot of the carb, below the 112. That will tell you what it was originally meant for. Yours has a hot idle compensator, and the heat tube comes in from the rear. The casting date is early 64. I'm thinking it's from a 65 FE block.