Surging and jets

[Anonymous]

Hey guys,
I recently replaced my autolite 1100 carb on my 66 mustang. Its an automatic, and everything is original on the engine. There seems to be some problems with this carb though. It studders when revving the engine up in neutral and off the line while in gear.
It also surges when going a steady speed. So i am wondering what you all think is the problem. The problem persists no matter how the timing is or how lean or rich, But it does seem to do a little better when running rich. So i am thinking that maybe the jets are too small? I think i remember seeing the main jet as 48.
What would be a good jet setup for this stock engine guys?
And lastly, where is the second jet located? I cant seem to find it to save my life.
Thanks for the help.

By the way, the engine runs perfect with no hesitations or surging(but its getting to old to work with). So I am 100% positive that there is a problem with the air/fuel mix on the rebuilt carb.

 

[kirkallen143]

Be sure to check your float level, too.

Kirk

 

[mustang652]

... I recently replaced my autolite 1100 carb on my 66 mustang. Its an automatic, and everything is original ... problems with this carb though. It studders when revving the engine up in neutral and off the line while in gear. ... I think i remember seeing the main jet as 48.

Currently running the same setup on my '65, the engine is from a '66 and I do have headers. Had the same problem back in Oct. As I was pressed for time, took the car to a local mechanic. He went through five of the rebuilds from one of the local major franchise parts stores before he found one that would actually run. Ended up costing me nearly $400 and still got what I think was a poor quality carb. When I pulled it apart a couple of days ago to check the jet for comparison on the rebuilds I'm doing for a tri-carb, it is stammped with a 48 and I noticed that it is obviously not an Autolite jet. As something seemed strange about the size just eyeballing the size of the jet, I crossed checked it using the shaft of my smalliest drill bit against a 56, a 60 and a 69. Shaft wouldn't fit in the 57, snug in the 60, loose in the 69 and very loose in the one marked "48". So it's got to be far larger than a 48. Who ever manufactured them must have reverse the numbers. I think it's more like an 84. Next time I have to buy a rebuilt, I'm going bact to Pony Carbs. Yes, even they have occational problems, but not 4 out of five as duds. Had I done that to begin with, I would have saved nearly 200. I've been told, that the biggest problem on the "parts store" rebuilds is that the rebuild on the power valve is of real poor quality. Don't know if that's true or not, but over the 16 years I've had the '65, I've gone through at least 12 or more carbs to get three that worked. The Pony Carb lasted the longest, got 7 years of flawless operation. Tried to recover the body of the one they traded, but found out too late about the exchange. If it's not to late, take it back and get another and keep doing it until you get one that works.

 

[CZLN6]

Howdy Back All:

Stang on the way- This is not a jetting issue. Is could be, in part, related to float setting, but more likely one or more of the orifaces are plugged or otherwise restricted.

Mustang 652 is absolutely right about rebuilt carbs. They are notorious for being poorly done. You are, almost always, better off to rebuild a good core then to buy a "Rebuilt". If you do have to go to a rebuilt you would be wise to disassemble, clean, inspect and record all parts, and reassemble yourself to be sure of what you have and that it is done right.

Once done you can get the most out of a carb rebuild by having good filters, gas and air, in place, using no more return spring pressure than neccesary to get a good return, and using a gas system cleaner periodically.

Another source of contamination to the 1100 carb is through the air intake for the hot air stove to the choke. Unfiltered air is pulled through the hole/stove in the exhaust manifold to the choke housing. This was not one of Fords better ideas.

The seemingly high price for a quality Pony Carb may not seem that high, considering what it takes to get a "good" rebuilt carb.

Adios, David

 

[mustang6]

Parts stores also intermix SCV and non-SCV Autolites like they are interchangeable when really they aren't.

 

[Anonymous]

I think my old carb has the SCV, but this new one doesnt have one.

The SCV is the round valve that has several small holes on the top of it, and it screws into the side of the carb near the vacuum, right?

Could this be the reason why it is not acting right?

 

[CZLN6]

Howdy Back:

A-haaa!!!!! Ain't it amazing that most carb problems are really ignition problems. Good catch Mustang6.

Yes, it could make the differences you are experiencing. Your Load-a-Matic distributor is no longer working as designed. It may also be a '67 or '68 Autolite, which has no SCV but also in downsized in the venturi, from 1.2" to 1.1". That equal a reduction in CFM from 185 to 150.

You will either need to get the right carb, or step up to a '67 and later distributor. I'd go for the right carb with the correct venturi.

By the way, there is no second jet in an 1100.

Adios, David