A
Anonymous
Guest
Hi Y'all,
I've just joined the forums here the other day in hopes of finding some specifics for the autolite 1100 carb used on our 66 Mustang 6 cylinder 200. After a few evenings and early mornings of playing with the carb, she’s back in action and running smooth. Here’s my story and hopefully it might help someone else out that might be having the same symptoms.
We’ve had this car for a number of years and had it towed home from the guy we bought it from because it would barely run, but it also had a sloppy front end. I did a leak down test on the engine just before I bought it and that’s what sold me on the car where as my wife liked it because it was pretty on the outside and that’s why she wanted it
. In any case, I finally got around to installing new upper & lower control arms, new ball joints, new idler arms, new sway bar bushings, new coils & leafs, new shocks, new brakes front and rear, new interior and other misc parts. But when it came time to take her on the road, she ran pretty badly.
Initially the car would not start and I found no fuel coming from the fuel pump. I was almost ready to buy a fuel pump, but wanted to try a quick try before shelling out more money. I poured fuel into the fuel line from the carb until the line was filled and let it sit a while before trying it again. Maybe this helped to somehow prime the pump or revitalize a seal, etc, because the fuel pump finally started to work where as before nothing came out of the fuel line when cranking the engine. I thought my problems were solved, but little did I know I was in for an exercise.
The car was very hard to start unless I poured fuel into the venturi, but at least now it would stay running with some work from the pedal. While driving, the engine would simply stop as if it were running out of fuel. Sometimes it would surge and die and sometimes it would pop very loudly (like a gun shot) once or twice upon decelerating from higher engine RPM. At one point when the car surged and stalled on the straights, I pulled it over to a safe spot, disconnected the fuel line and popped off the top of the carb with my cordless screwdriver and found the float bowl was nearly empty (a lean stall). I also noticed the float needle was stuck up in the valve shutting off the fuel supply. It turns out the inside of the valve had a burr and the needle sometimes stuck closed. I also noticed the accelerator pump wasn’t working, so I drove the car home to take the carb apart. It was dirty inside, so I cleaned everything out and put her back together and now the AP worked. I also noticed the choke was put back together incorrectly and the wrong manifold gasket was used. I didn’t want to pony up the money for a new carb, so I bought an $18 carb rebuild kit from the local parts store and got everything back in order with new & correct gaskets, balls, float needle & valve, etc, and reset the float height to the specified 1 & 3/32â€, the AP roll pin height to spec, etc. Even thought I could blow through the existing fuel filter, the new fuel filter had less resistance when blowing through it, so of course I also used a new fuel filter.
The car ran better, but it would still surge on the straights at part and or full throttle and sometimes it would die. Decelerating from higher engine RPM sometimes caused the car to run rough and or stall in addition to a loud pop / bang (like a gun shot) before it died. My wife noticed that every once in a while the car would poof black smoke upon starting up and I finally got to see it and it was a pitch black carbon poof (not oil), all of which lead me to believe the fuel/air mixture was running too rich. When I was able to pull it over to a safe spot upon stalling, I pulled the fuel line and popped off the top of the carb and found the fuel bowl nearly full with fuel. It just seemed to me that the bowl shouldn’t be this full and that bothered me. I found this same condition a couple more times after surging / stalling and knew I had to lower the fuel level in the bowl to lean things out at some point. I was wondering about the main jet size and thought I had a 169, but after I put it under a magnifying glass, I found I had a 68F. I don’t know where that fits into the scheme of things, but I’m anxious to get some other jet sizes and see where things go from there.
While thinking about all this, I also wanted to quickly check the vacuum advance and since I couldn’t find my vac gauge, I simply sucked on the line from the carb to see if the advance was working (dist cap off of course) and it barely moved. I sprayed carb or brake cleaner into the line from the carb end and it filled the line up without coming out the other end. Hmmm…So I put some compressed air on the hose and it blew some chunks of stuff out the hose and into my collection jar for examination. The vac advance was now working nicely…whoohoo! But, issue of surging / stalling and the loud pop / stall upon deceleration from higher engine RPM still remained.
I made a radical adjustment to the float from the specified 1 & 3/32†to 1 & 7/32†and my problems were almost solved. Much less surging and stalling and no more loud pop/bang upon deceleration from high engine RPM. Now she would occasionally stall when making sharp turns and only occasionally surged on a long straightaway at constant engine RPM. It was a night and day difference!
After playing around with the float height, I finally settled on making the float height ‘exactly’ at 1 & 5/32â€. This was the magic number for me because this car ran trouble free for more than 20 miles of sharp turns, hills, and long straight-aways. There were no stalls, no surges, no loud pops / bangs on decal from high engine RPM. It ran flawless for the first time since I’ve been playing with it.
The interesting thing is that I ran into another guy at the local auto parts store this evening while I was picking up some bolts and he said he had a 6 cylinder Mustang like mine, but it had been surging and stalling so he parked it last year and almost forgot about it. We got to talking and he said he had paid a local shop to diagnose the problem and go through the carb, but the problem was never resolved and he simply parked the car and it’s been covered ever since. I went over to his house this evening and cleaned his carb and changed his float height from where it was at 1 & 1/6†to 1 & 5/32 and this car ran great. The guy said this is the first time in a long while that his car ran perfect without surging and or stalling.
I searched these forums for a specific float height and found tons of talk about the autolite 1100 and plenty of talk about surging and or stalling, but I could not find a specific number for the float height on this carb. If anybody here is having problems with their engine surging or stalling and they have an autolite 1100 carb, then maybe give the 1 & 5/32†float height a try and see if that helps. It definitely made all the difference for me!
Another tip for anyone who is serious about accurately setting their float height is to source a float height gauge. I’ve worked on plenty of carbs in the past, especially on motorcycles and happened to have one on hand, but you can get a decent float height gauge made by Kowa Seiki Tools through your local Honda Motorcycle parts department by ordering Honda PN# 07401-0010000. The list price of this tool from your Honda dealer is $23.50 and your Honda dealer may even give you a better price, but be aware that many other places sell this ‘exact’ same tool under the Kowa brand name for up to $60, so don’t get ripped off! It works perfect for small bore carbs like the autolite 1100 and allows a very accurate & consistent measurement to be taken.
It’s simply a stamped piece of steel that allows one leg to slide left and right so the legs can sit on the gasket surface. One leg has graduated markings on it and a ‘L’ shaped bar slides up and down the leg that has graduated markings and rests on the highest part of the float. You can simply read the number next to the adjuster bar or measure this distance on this tool with a digital caliper for even more precision. You can probably find a picture of this gauge by googling the part number if you’re interested in what it looks like. It’s not a tool for everyone and they’re simple to make for a machinist, but this tool has some in handy for me and there might be one or two people here who also might find it helpful to them.
I wish I had dug into this project sooner because I’m really starting to like this little beauty of an engine!
I've just joined the forums here the other day in hopes of finding some specifics for the autolite 1100 carb used on our 66 Mustang 6 cylinder 200. After a few evenings and early mornings of playing with the carb, she’s back in action and running smooth. Here’s my story and hopefully it might help someone else out that might be having the same symptoms.
We’ve had this car for a number of years and had it towed home from the guy we bought it from because it would barely run, but it also had a sloppy front end. I did a leak down test on the engine just before I bought it and that’s what sold me on the car where as my wife liked it because it was pretty on the outside and that’s why she wanted it
. In any case, I finally got around to installing new upper & lower control arms, new ball joints, new idler arms, new sway bar bushings, new coils & leafs, new shocks, new brakes front and rear, new interior and other misc parts. But when it came time to take her on the road, she ran pretty badly.Initially the car would not start and I found no fuel coming from the fuel pump. I was almost ready to buy a fuel pump, but wanted to try a quick try before shelling out more money. I poured fuel into the fuel line from the carb until the line was filled and let it sit a while before trying it again. Maybe this helped to somehow prime the pump or revitalize a seal, etc, because the fuel pump finally started to work where as before nothing came out of the fuel line when cranking the engine. I thought my problems were solved, but little did I know I was in for an exercise.
The car was very hard to start unless I poured fuel into the venturi, but at least now it would stay running with some work from the pedal. While driving, the engine would simply stop as if it were running out of fuel. Sometimes it would surge and die and sometimes it would pop very loudly (like a gun shot) once or twice upon decelerating from higher engine RPM. At one point when the car surged and stalled on the straights, I pulled it over to a safe spot, disconnected the fuel line and popped off the top of the carb with my cordless screwdriver and found the float bowl was nearly empty (a lean stall). I also noticed the float needle was stuck up in the valve shutting off the fuel supply. It turns out the inside of the valve had a burr and the needle sometimes stuck closed. I also noticed the accelerator pump wasn’t working, so I drove the car home to take the carb apart. It was dirty inside, so I cleaned everything out and put her back together and now the AP worked. I also noticed the choke was put back together incorrectly and the wrong manifold gasket was used. I didn’t want to pony up the money for a new carb, so I bought an $18 carb rebuild kit from the local parts store and got everything back in order with new & correct gaskets, balls, float needle & valve, etc, and reset the float height to the specified 1 & 3/32â€, the AP roll pin height to spec, etc. Even thought I could blow through the existing fuel filter, the new fuel filter had less resistance when blowing through it, so of course I also used a new fuel filter.
The car ran better, but it would still surge on the straights at part and or full throttle and sometimes it would die. Decelerating from higher engine RPM sometimes caused the car to run rough and or stall in addition to a loud pop / bang (like a gun shot) before it died. My wife noticed that every once in a while the car would poof black smoke upon starting up and I finally got to see it and it was a pitch black carbon poof (not oil), all of which lead me to believe the fuel/air mixture was running too rich. When I was able to pull it over to a safe spot upon stalling, I pulled the fuel line and popped off the top of the carb and found the fuel bowl nearly full with fuel. It just seemed to me that the bowl shouldn’t be this full and that bothered me. I found this same condition a couple more times after surging / stalling and knew I had to lower the fuel level in the bowl to lean things out at some point. I was wondering about the main jet size and thought I had a 169, but after I put it under a magnifying glass, I found I had a 68F. I don’t know where that fits into the scheme of things, but I’m anxious to get some other jet sizes and see where things go from there.
While thinking about all this, I also wanted to quickly check the vacuum advance and since I couldn’t find my vac gauge, I simply sucked on the line from the carb to see if the advance was working (dist cap off of course) and it barely moved. I sprayed carb or brake cleaner into the line from the carb end and it filled the line up without coming out the other end. Hmmm…So I put some compressed air on the hose and it blew some chunks of stuff out the hose and into my collection jar for examination. The vac advance was now working nicely…whoohoo! But, issue of surging / stalling and the loud pop / stall upon deceleration from higher engine RPM still remained.
I made a radical adjustment to the float from the specified 1 & 3/32†to 1 & 7/32†and my problems were almost solved. Much less surging and stalling and no more loud pop/bang upon deceleration from high engine RPM. Now she would occasionally stall when making sharp turns and only occasionally surged on a long straightaway at constant engine RPM. It was a night and day difference!
After playing around with the float height, I finally settled on making the float height ‘exactly’ at 1 & 5/32â€. This was the magic number for me because this car ran trouble free for more than 20 miles of sharp turns, hills, and long straight-aways. There were no stalls, no surges, no loud pops / bangs on decal from high engine RPM. It ran flawless for the first time since I’ve been playing with it.
The interesting thing is that I ran into another guy at the local auto parts store this evening while I was picking up some bolts and he said he had a 6 cylinder Mustang like mine, but it had been surging and stalling so he parked it last year and almost forgot about it. We got to talking and he said he had paid a local shop to diagnose the problem and go through the carb, but the problem was never resolved and he simply parked the car and it’s been covered ever since. I went over to his house this evening and cleaned his carb and changed his float height from where it was at 1 & 1/6†to 1 & 5/32 and this car ran great. The guy said this is the first time in a long while that his car ran perfect without surging and or stalling.
I searched these forums for a specific float height and found tons of talk about the autolite 1100 and plenty of talk about surging and or stalling, but I could not find a specific number for the float height on this carb. If anybody here is having problems with their engine surging or stalling and they have an autolite 1100 carb, then maybe give the 1 & 5/32†float height a try and see if that helps. It definitely made all the difference for me!
Another tip for anyone who is serious about accurately setting their float height is to source a float height gauge. I’ve worked on plenty of carbs in the past, especially on motorcycles and happened to have one on hand, but you can get a decent float height gauge made by Kowa Seiki Tools through your local Honda Motorcycle parts department by ordering Honda PN# 07401-0010000. The list price of this tool from your Honda dealer is $23.50 and your Honda dealer may even give you a better price, but be aware that many other places sell this ‘exact’ same tool under the Kowa brand name for up to $60, so don’t get ripped off! It works perfect for small bore carbs like the autolite 1100 and allows a very accurate & consistent measurement to be taken.
It’s simply a stamped piece of steel that allows one leg to slide left and right so the legs can sit on the gasket surface. One leg has graduated markings on it and a ‘L’ shaped bar slides up and down the leg that has graduated markings and rests on the highest part of the float. You can simply read the number next to the adjuster bar or measure this distance on this tool with a digital caliper for even more precision. You can probably find a picture of this gauge by googling the part number if you’re interested in what it looks like. It’s not a tool for everyone and they’re simple to make for a machinist, but this tool has some in handy for me and there might be one or two people here who also might find it helpful to them.
I wish I had dug into this project sooner because I’m really starting to like this little beauty of an engine!
