Autolite 1100 Carburetor

Autolite 1100 carburetor parts.All technical information including videos assume parts used are our brand. Parts from other sources may not install, or function the same way.
About the Autolite 1100 Carburetor

  • The Autolite 1100 one-barrel carburetor was included on 170″ & 200″, 1963-69.
  • 1963-1967 (some) came with a spark control valve.
  • 1968 – The venturi size was changed to 1.10 and there was no control valve.
    The distributor was changed to use a mechanical advance
    instead of using the venturi vacuum previously.
  • 1967-1969
    – Two diaphragms were used. The added
    diaphragm is used as an anti stall dashpot. Only one diaphragm was used prior to 1967
  • Correct venturi size for Mustangs was 1.10″, or 1.20″
  • When no tag is present, Identification can be done by inspecting the base. You can sometimes find a Ford part number there.

Buy your Autolite 1100 carburetor kit here.

Free Autolite 1100 manuals

1968-69 Autolite 1100

Power Valve

At higher speeds, the engine vacuum drops which causes the power valve to open and allow more fuel to flow.
Autolite 1100 Choke

Do not remove the power valve assembly when rebuilding, but it does need to be free to easily move up and down. For sticky power valves spray liberally with silicon spray lubricant and work it up and down until it is free. Worst case is you will have to remove the clean out plug on the top of the carburetor so that you can get at the cylinder for cleaning. You will need a new clean out plug, or patch up the old plug with JB weld (don’t get any inside). A surge at high speeds (steady throttle) might indicate a power valve
problem. Change the power valve timing to open sooner (at less throttle opening) by adding additional calibrating shims, on power valve rod (see illustration above). If less than 4 shims found on rod, add 4 shims; if more than 4 shims found on rod, add fewer number. Total number of shims on rod must not exceed 8. These shims are not produced and you only want to take the power valve apart as a last resort.

Autolite 1100 Main Jet

This is where the Autolite 1100 main jet resides. Due to the difference in gasoline, the jet size that was originally installed on the 1100 isn’t that relevant anymore. Be sure you are using the correct jet size, otherwise you chance ruining your engine. Test your main jet
by running your vehicle for 20 minutes at a sustained speed. Pull a spark plug and look at the color. Gray is perfect. White means you are too lean and need to move up one size.
Black is too much fuel and you need to move down one size. Do this one size at a time until you get a good gray colored plug. This test is only valid when your engine and electrical system are good condition.
Autolite 1100 Jet

1966 Rough Idle & Poor Fuel Economy Correction.

This condition may be caused by the fuel bowl vent valve being out of adjustment. Check and adjust the vent valve each time the carburetor idle speed adjustment is made. 

Buy your Autolite 1100 Main Jets.

Did you lose your check weight?

Autolite 1100

These are no longer available, but you can make your own. Use a 3/16″ aluminum rod, cut 9/16″ long. File the end a bit as pictured. Weight will end up being about 1 gram.

Watcha video about On The Bench Adjustments

Watch a video about rebuilding the Autolite 1100 carburetor. Part 1 – Teardown

Question
I seem to have a problem with my carb that I rebuilt recently. It is a C8PF-D on my 1963,170 cu in Falcon with auto trans. Its a manual choke and has the spark control system and a diaphram on each side. We adjusted the mixture screw till it ran nice and took it for a small drive. Upon returning it would not idle hardly and was running very rough. We adjusted the mixture screw again and it started runnning properly agian. The next drive we took it ran great, but when we arrived home the same rough running and no idle was present agian. It acually died on us instead of idling. My question is if the mixture
screw is backing itself off due to vibrations etc.? Could the screw or spring be worn out or could it be the carb hole and threads worn out? I hope you have run across this before and can point me in the right direction. I thought about loctite to hold it, or maybe a new
spring and screw.

Answer
1st off don’t use anything on the threads. That would probably ruin the carburetor. It does seem the screws are moving from vibration. I would replace the idle mixture screw and spring.

Watch a video about the Autolite 1100 Flooding Troubleshooting

 


I am having an issue with my autolite 1100 stumbling when under way. Everything is fine at rest. I notice if I sit on the fender and rock the car the engine begins to stumble. When I set the float level I used the Fuel system service instruction worksheet provided in your rebuild kit and it stated to set the float level to 1 – 3/32 for my 65 Mustang 200 A/T, which I did. Do you think its possible I would need to set the float level higher or do I possibly have something else going on? Fuel pump filter and strainer are all 2 months old. As is the carb rebuild.

The 1st thing that comes to mind is that the flow bowl is warped. Check my video about fixing the 1904 with heat. Same idea.

Recent Posts

Adjusting the Idle Mixture

The Carburetor Idle Circuit and Adjusting the Idle Mixture

The idle circuit is in effect only when idling. Once RPM increases above idle, the Idle mixture screws are no longer in play. If you have the idle RPM set too high, your idle mixture adjustment will be irrelevant. When you turn the idle mixture screw in all the way and the engine doesn’t change, you could have the idle RPM set too high. For example if it was at 1,000 RPM. On the other hand if the idle is normal, then you have a problem in the carburetor, or possibly a vacuum leak.

The idle mixture screws sets the mixture of fuel and air during idle RPM.

Single barrel carburetors will have one idle mixture screw while 2 barrel and 4 barrel usually have 2 idle mixture screws.
You can clean your idle mixture screws by buffing them off with a wire wheel.
Inspect the screw for grooves. Grooves are created when the screw is turned in too tight. Replace any damaged or bent screw.
Inspect the screw hole to make sure it is clear. When you blow through the hole you should get air inside the bore.

For Rochester Quadrajets pick up a idle mixture adjusting tool at most any part store. The tool bends which will make adjusting easier.

When assembling the carburetor turn the idle mixture screws in all the way, gently seat, then turn it out about 1 1/2 turns.

Bring the engine up to operating temperature.
Make sure the choke valve is completely open.
You may have to rev the engine slightly so that the fast idle cam moves to the idle position.
Adjust the idle to specification.

There are a couple of ways to adjust the idle mixture.

1. Using a vacuum meter
Hook the vacuum meter to one of the vacuum ports on the intake, or the carburetor.
Take turns with each idle mixture screw.
Turn each screw out a bit for a start (maybe 1 turn).
Turn each screw in 1/4 of a turn and wait for a second for the vacuum meter to catch up.
Do this until you get the smoothest idle and the vacuum meter stays steady.

2. By ear
Take turns with each idle mixture screw.
Turn the screw out 1 turn to start.
Turn the screw in 1/4 and wait for a second for the engine to catch up.
Keep doing this until the RPM starts to drop.
Turn the screw back 1/4 – 1/2 turn.

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