Does anybody know, is there any particular mistake you could make rebuilding the autolite 4100 that would cause the engine to chug black smoke at idle and run rich over the entire RPM range? That is the situation I am facing.
This is a great video I have a 4100 and I'm in the process of rebuilding it so just what I needed to watch for it to make more sense of what I should be looking for
thank you!!!!!!!!!!!!!!!!!!!!!working on one right now, driver side idle screw has no effect on idle when closed,i believe its the air bleed as I can blow through the screw hole w carb spray and it comes out the idle hole in the venturi.
Wish I had found this video before I did my rebuild. I'm 99% certain I got them all cleaned out, but it would've been nice to have kind of a checklist... Oh well. If it doesn't run right, I can always take it apart again and make sure I hit every hole you've got shown here. :-)
In the process of rebuilding mine. I found that the drivers side emulsion tube wouldn't get any fuel sprayed through the center tube if I sprayed cleaner through the metered bleed to the side of it. It'd come out the vent hole for it. That was very hard to get unplugged, explains why the drivers side idle mixture screw didn't do anything.
on the bottom side of the primary booster. the Two outer holes that are metered. what is the purpose of metering jets? Reason I am asking is that on a "D2" booster they are rather big without a jet installed and the long inner tubes are much smaller then usual. How does this effect the idle quality?
I found the old 4100 4barrel carb that my late father used on this 64 Galaxie with the 352 40 years ago. It is in bad shape; however in this carb the main jets are 52F and the secondary are 68F. I need to pull the air horn and find out what my current 4100 has.
That sounds like the Hi-Po spec'ed jetting from a 289 engine. If you have a regular 352 that carb might have been causing it to run too rich. The 1.12 venturi size is for 600 CFM, and that might be a size or two bigger than stock (which might cause less efficient atomization). You might want to double check the carb specs for your engine.
So I I feel my 4100 is running lean and I want to try the next size up jet, do I need to do any thing with the ventures on top? The ones that you remove with the hollow screw and the check ball. Are they all the same size? My carb is stamped 1.12.
The venturis are sized based on the maximum airflow of the engine, which is determined by the displacement and volumetric efficiency. Therefore you shouldn't change them unless something is physically different with the engine (bored out, stroker, intake manifold, etc). If the engine is running lean the correct fix is to just change the jet, but make sure all the passages are clean first, and you've ruled out any vacuum leaks. If the engine ran fine previously I would be very hesitant to change the jet unless you are sure it has always been the wrong size.
@@jewllake From what I can find, you should have between a 048 and 050 size main jet. Look for the number stamped into it. If you think it's running lean, run it down the highway, shut it off, and read the plugs. Not sure what to make of your timing, perhaps your dist needs to be recurved or your timing marks are off. New carb might be burning more efficiently so perhaps you're noticing an existing timing issue.
I did rebuilt my Autolite 4100 and I’m having some trouble setting it up, it starts but doesn’t hold the car running, what is most common mess up when reinstall it?
I'm having the same problem. I screwed something up and now the thing runs rich, chugs black smoke, and won't even stay running when you put the car in gear.
👍… Appreciate the advice… This carburetor of mine the Motorcraft 4100 has never opened the secondaries since I owned it. Had a rebuild done, changed rear diaphragm twice, sprayed out air passages. The only things not not tried are … add a gasket with the diaphragm as some of them are not sold together, I have not replaced the vacuum advance and I have not replaced the larger intake spacer gasket underneath the carburetor…. Any tips or tricks would be terrific?
@@robertswain8665 Secondaries are vacuum operated. Attach a small hose to the vacuum pickup tube and suck on it (syringe suggested) with the throttle open to verify operation. I talk about the tube at about 14:00. If the secondaries don't open, it may be because you don't have enough manifold vacuum, check with a vacuum gauge. Could be not enough advance, not enough load, or big vacuum leaks. Revving it in neutral might not open the secondaries because there's not enough load. Hard to test without a dyno, I basically checked the secondaries on the bench and trust that it works right on the car.
In one video you completely demystified carburetors for me! I've always looked at them like a black box. This video is awesome! Thanks!
Excellent explanation of the function of the holes and flow of fuel and air. Thank you for your time.
I"ve rebuilt several of these and after watching your video.....I knew nothing about this carb....but I do now. Thanks!
Does anybody know, is there any particular mistake you could make rebuilding the autolite 4100 that would cause the engine to chug black smoke at idle and run rich over the entire RPM range? That is the situation I am facing.
Float levels too high or floats are stuck open
This is a great video I have a 4100 and I'm in the process of rebuilding it so just what I needed to watch for it to make more sense of what I should be looking for
Excellent tutorial!
Thanks for the video the first good explanation ... is very helpful
thank you!!!!!!!!!!!!!!!!!!!!!working on one right now, driver side idle screw has no effect on idle when closed,i believe its the air bleed as I can blow through the screw hole w carb spray and it comes out the idle hole in the venturi.
Wish I had found this video before I did my rebuild. I'm 99% certain I got them all cleaned out, but it would've been nice to have kind of a checklist... Oh well. If it doesn't run right, I can always take it apart again and make sure I hit every hole you've got shown here. :-)
The plating on your carb is very nice!!
So when people tell you to make sure you clean all the holes.. THANK YOU!
Thank you
good vid.
In the process of rebuilding mine. I found that the drivers side emulsion tube wouldn't get any fuel sprayed through the center tube if I sprayed cleaner through the metered bleed to the side of it. It'd come out the vent hole for it. That was very hard to get unplugged, explains why the drivers side idle mixture screw didn't do anything.
on the bottom side of the primary booster. the Two outer holes that are metered. what is the purpose of metering jets? Reason I am asking is that on a "D2" booster they are rather big without a jet installed and the long inner tubes are much smaller then usual. How does this effect the idle quality?
are the venturis supposed to have a weight on top of the ball?
I found the old 4100 4barrel carb that my late father used on this 64 Galaxie with the 352 40 years ago. It is in bad shape; however in this carb the main jets are 52F and the secondary are 68F. I need to pull the air horn and find out what my current 4100 has.
That sounds like the Hi-Po spec'ed jetting from a 289 engine. If you have a regular 352 that carb might have been causing it to run too rich. The 1.12 venturi size is for 600 CFM, and that might be a size or two bigger than stock (which might cause less efficient atomization). You might want to double check the carb specs for your engine.
So I I feel my 4100 is running lean and I want to try the next size up jet, do I need to do any thing with the ventures on top? The ones that you remove with the hollow screw and the check ball. Are they all the same size? My carb is stamped 1.12.
The venturis are sized based on the maximum airflow of the engine, which is determined by the displacement and volumetric efficiency. Therefore you shouldn't change them unless something is physically different with the engine (bored out, stroker, intake manifold, etc). If the engine is running lean the correct fix is to just change the jet, but make sure all the passages are clean first, and you've ruled out any vacuum leaks. If the engine ran fine previously I would be very hesitant to change the jet unless you are sure it has always been the wrong size.
@@jewllake From what I can find, you should have between a 048 and 050 size main jet. Look for the number stamped into it. If you think it's running lean, run it down the highway, shut it off, and read the plugs. Not sure what to make of your timing, perhaps your dist needs to be recurved or your timing marks are off. New carb might be burning more efficiently so perhaps you're noticing an existing timing issue.
@@TechnicalLee Thanks!!!
I did rebuilt my Autolite 4100 and I’m having some trouble setting it up, it starts but doesn’t hold the car running, what is most common mess up when reinstall it?
I'm having the same problem. I screwed something up and now the thing runs rich, chugs black smoke, and won't even stay running when you put the car in gear.
Hi, Do you know if the secondaries pump fuel in the carburetor, just as the primaries do?
If so,at what point do they initiate the fuel?
No, the accelerator pump only squirts the primaries. The secondaries are vacuum-draw only.
👍… Appreciate the advice… This carburetor of mine the Motorcraft 4100 has never opened the secondaries since I owned it.
Had a rebuild done, changed rear diaphragm twice, sprayed out air passages. The only things not not tried are … add a gasket with the diaphragm as some of them are not sold together, I have not replaced the vacuum advance and I have not replaced the larger intake spacer gasket underneath the carburetor….
Any tips or tricks would be terrific?
@@robertswain8665 Secondaries are vacuum operated. Attach a small hose to the vacuum pickup tube and suck on it (syringe suggested) with the throttle open to verify operation. I talk about the tube at about 14:00. If the secondaries don't open, it may be because you don't have enough manifold vacuum, check with a vacuum gauge. Could be not enough advance, not enough load, or big vacuum leaks. Revving it in neutral might not open the secondaries because there's not enough load. Hard to test without a dyno, I basically checked the secondaries on the bench and trust that it works right on the car.
This is good idea… will do this.
Thank You,
Rob
how much CFM is that ?
I think this one is 1.12" venturis so 600 CFM.
so its not really that complicated