Autolite 1101 problems

I'm still tracking down a vacuum leak that is causing shuddering and sluggish start.

I used ether to detect a leak around the base of the carb. I order a carb rebuild kit to replace the gaskets.

Check balls came out during disassembly but I'm pretty sure they are in the right place.

Float is set to 1 3/32" with a metal float

Problems: I can't get it to tune. The idle mixture screw has almost no effect. While driving, the car stall when I even just tap the brake, to the point that it is dangerous and undrivable. I've tuned it with a tach and vacuum. Idle mixture screw does almost nothing.

Any ideas about what I did wrong with the carb?

Also, just to be clear... the 1101 has one dashpot and no spark valve. That makes for 3 check balls right?

Hi, rebuilding a carb is always an adventure. When I do it I take my time, savor the experience. I follow the instruction to the letter and clean all the parts 3 or 4 times. So you can take it apart again (no harm, no foul) and make sure all the right parts are in all the right places. But the concern is the vacuum leak. It sounds bad so maybe a couple of things are going on. Check that the throttle shaft is not too sloppy in the carb because if it is too worn then it could cause your vacuum leak. By the way, I usually do not remove the shaft when I rebuild a carb, I just clean it and check it out for slop. One problem I do get on my Bronco is the base plate can loosen from the body every decade or so, but I don't think that is your problem. I doubt it is old gasket not cleaned off, but make sure about that. The main point (finally) is if there are other problems you are not ready to adjust your carb, and it sounds like you are looking for a major vacuum leak, not just a worn throttle shaft. Good luck

U Go Ron,
2X his insights...

I agree with Ron. Don't assume where the check balls were is right, you've got to follow the diagram precisely and the carb must be thoroughly clean. Also there should be a weight above one of the balls, look at the diagram. If that weight is missing, you'll have to make one out of a piece of aluminum rod. My 1100 was missing a ball, had a another misplaced and was missing the weight. Barely ran before the rebuild. Also the check balls should be seated with a small drift to ensure they seal well to their seats.

http://www.carburetor-parts.com/Autolit ... p_281.html

Econoline":yn69wbf6 said:

http://www.carburetor-parts.com/Autolite-1100-1101-Technical_ep_281.html

Click to expand...

Mike's is great even if not buyin:
prt #s, exploded diagrams, assembly vids...

"Problems: I can't get it to tune. The idle mixture screw has almost no effect. While driving, the car stall when I even just tap the brake, to the point that it is dangerous and undrivable. I've tuned it with a tach and vacuum. Idle mixture screw does almost nothing."


This does sound like a possible vacuum leak. Not too long ago, I worked on a 4.9L which idled quite high [~1000 RPMs], ran poorly, jerked on deceleration and @ idle speed, pulled 18.5" Hg. A comparable engine [mine] pulls ~21.0" @ idle. I tried every trick I knew to find the leak. I used carb cleaner and checked all vacuum lines on the engine, HVAC system, PCV valve and power brake booster. Using needle nose pliers, I pinched each and every vacuum line. I sprayed along where the intake manifold attaches to the engine. I even made a block-off plate for the EGR valve. None of this worked. One time, it seemed that when the carb cleaner was sprayed at the #5 intake runner [manifold], the idle would slightly change, but then it would not repeat???

I saw a trick on Youtube and went out and purchased a $0.69 cigar. I covered the mouth of the carburetor with duct tape [engine off, of course!] and took the vacuum tube which had been disconnected from the temp. sensor on the air cleaner. This hose was still connected to the vacuum tree. I lit that bad boy and took in a deep draw and blew into the vacuum hose. I placed my thumb over the open end, while taking another draw. With the second blow into the vacuum hose [that quick!], I could see smoke coming out from under the carburetor toward the engine. I couldn't believe my eyes. The vacuum tree is screwed into the intake manifold and has numerous ports, some unused. There was one which I had never seen at the bottom of the vacuum tree and pointed down towards the ground. [Keep in mind that on a 1984 4.9L feedback equipped engine, there are yards of vacuum hoses and wires obstructing the view.] Well, the rubber cap had a large hole in the center. This cap likely was the factory original and is nearest the exhaust manifold, so is exposed to more heat. Since it was oriented downward, I could not see it, hear it or hit it with the carb. cleaner spray. In hindsight, the time I thought the idle changed, the spray must have bounced off the engine block and partially hit the open port.

Prior to replacing the rubber cap, the idle air mixture screw was turned out ~5 turns. Immediately after the repair, it needed to be turned in ~2 1/2 turns. The vacuum increased to 21" Hg and the deceleration jerking stopped.

For 1/2 of a cigar [~35 cents], it was a cheap and quick fix.

I hope this might help and I apologize for the very long post.

Update:
I went back to the diagram to check the check balls. I did have it wrong. I think...

One problem that I'm having is the diagram is for autolite 1100 and I have 1101. The check balls are a noticeable difference between these two carbs. the 1101 doesn't have as many places for the balls. Going by the diagram, I decided to only replace #27 as that was the only one the correlates to the 1101. No weight this time. Runs great now.

Regarding the vacuum leak. What a pain! I will try the cigar trick.

this is weird, but I get a consistent rev when I spray ether on the numberplate screws at the back of the intake near the throttle linkage. at first I thought it had just splashed up into the carb, but I shielded the carb with a piece of cardboard and got consistent results on the screws. There's a coat of paint on them, but I guess it's possible they have rusted or wiggled. I slopped so RTV on them and it helped.

Next question is the distributor line. I'm drawing from the ported vacuum at the top of the carb. It draws less the 5" at idle. Manifold draw is between 14-15" at idle.

Is this normal? forgive my ignorance...