Hesitation Rebuilt Carburetor

[cheech63]

!972 Ford F100 302 2bbl. Automatic. Can anyone suggest what too look for after this carburetor (Motorcraft 2100) was completely taken a part, cleaned and blown out (w/air compressor) and now it has a constant hesitation for one second upon acceleration from either a stand still or while cruising. If I feed the gas very lightly it's okay, but not if I accelerate normally or quickly. For sure it did not do this at all before the rebuild. My set up is , Points .17 gap, initial timing set at 10 BTDC, vacuum advance working. no vacuum leaks. Re- checked the float level (wet) and the accelerator pump diaphragm as well as that rubber orange umbrella thingy, but didn't see anything wrong. Reason for the carb rebuild was it failed two smog tests. Now after the rebuild it has passed the smog test, but now it has this new hesitation problem that it did not have before ?. I'm sure this problem has been experienced by others here, so I'm hoping to find someone that has cured this problem. As I'm at a loss, outside of buying a new carburetor.

[fordman]

normally the accelorator pump diaphram in the carb is the problem with a slight hesitation like that. but since you say you replace or rebuilt the carb. maybe something else is wrong. did you put the arm to the diaphram back in the same hole it came out of?

[JMcTurnan]

Yes fordman is exactly right normally the accelerator pump, sometimes though timing. I have no suggestions, but I have a good running 2bbl carburetor here I will sell you if you like.

[JMcTurnan]

You made sure the spring is good in there right?

[QC]

The plate the points mount on is worn out. Disconnect and plug the vacuum advance hose and see if it gets better. If it does you need a new breaker plate.

[flyboy2610]

The plate the points mount on is worn out. Disconnect and plug the vacuum advance hose and see if it gets better. If it does you need a new breaker plate.

Mines hesitates as well from a stop. I tried this, and no change. You think the accelerator pump diaphragm is shot?

[JMcTurnan]

What do you mean by hesitation, like a slight stubble, or hesitation when your trying to race with your foot to the floor?

[flyboy2610]

What do you mean by hesitation, like a slight stubble, or hesitation when your trying to race with your foot to the floor?

Lack of smooth acceleration from a stop. I'm guessing it's time for a rebuild. I have no idea when or if it's ever been done.

[fordman]

the main key that tells me the diaphram is bad or going bad is if it stumbels from a stop but you can let off a little and go anyway.

[cdeal28078]

If the vacuum advance test doesn't make a change to it back out the air/fuel screws about 1/4 turn each and see if it gets better.
clint

[cheech63]

Well I looked into the excellerator pump once again and while fideling around in there and disturbing that new rubber orange color umbrella thingy, the stem broke off pretty easily, (bummer) now the only other one that came in the carb rebuild kit that is some what simular to that flimmsy orange thing, is a black thicker rubber (umbrella type) thing which looks more like a plug type of thing. Anyway that's all I had to use to replace the new one I had just destroyed. The auto parts store say you must by a new carb kit to get a new orange one(rubber umbrella), as they don't sell them alone?....

Anyway none of the above made any difference at all, still hesitates exactly as before.

So my next thing to look at (member suggested) is the distributors advance plate, but I don't think in my case this is where the problem is, because I did not have this hesitation problem before the carburetor was removed for a clean out.
Damm emmisson control laws out here is a real pain in the ass, my truck was running just fine before, and without any hesitaions.

Hey the fellow that mentioned he has a used 2BBL motocraft 2100 carb for sale, hopefully it is deffinitly known to be problem free and it's for a 1972 f100 302 w/automatic trans, please let me know the cost + shipping to Henderson, NV 89074 . I may just have to go that route if I can't find what caused this annoying hesitation problem.

[cdeal28078]

See if there is a Speed shop in your area. I don't know if that orange thing is the same as what is in a Holley carb but sure sounds like it. I bet the speed shop has bags of them for a Holley and would probably give you one if you were nice to him. Worth checking on
clint

[jzjames]

Check your distrib. like he said, and your advance timing. Its possible the out of tune components were all adjusted to each other and when you put in the new carb kit, it didnt jive with the others.

[cheech63]

Hesitation problem solved. Thanks to all for the very helpful suggestions which gave me the push and determination to zero in on what was causing the hesitation. After going over most of the suggestions offered, I sat back today and thought, what didn't I look at or do more than twice with this carburetor, then it hit me. So off I went to the bone yard and came home with the cure.
Removed the top of the carb and float, unsrewed the two #47 jets and screwed in two well cleaned up #57 jets.
BADA BING problem solved. I now have my joy back running as it should.

I know that this is a big swing in jet size, but at least the culprit was discovered, even if I have to drop down in jet sizing if it gulps to much fuel I'll do so to find the happy medium. All I know now is I'm a happy camper. And perhaps this could help someone else as well.
Thanks to all.