All Small Six Carb help (autolite 1100)

[witchhunter467]

Hi everyone,
I’m working on my '65 Mustang with the 200ci inline-six and the Autolite 1100 (1V). I recently did a rebuild on the carb because of a fuel leak, but things have actually gotten worse.
The Main Issue: Fuel is spraying out of the top of the accelerator pump diaphragm housing. It was doing this before, but after the rebuild, it’s even more prevalent. During the teardown, I discovered that the pump discharge weight (the one that sits on the check ball) was completely missing. The carb currently has all three check balls, but no weight.
The Symptoms:
Significant fuel spray from the top of the pump cover when the throttle is moved.
I’m hearing a new "sucking/vacuum" noise coming from the carb/motor area that wasn't there before.
The car idled fine before the rebuild, but now I have to hold the throttle open and rev it out to get it to stay running (though I suspect I just need to re-tune the idle screws once the leak is fixed).
My Questions:
The Leak: Given that it's spraying out the top of the diaphragm, is this almost certainly a warped cover?
The Missing Weight: Would missing that discharge weight cause enough back-pressure to force fuel out the seal like this?
The Fix: Should I just order the missing weight and Mike’s Carburetor support plate to try and save this casting, or am I better off spending the $400 on the N1904 replacement? I’m worried this carb might be a "lost cause" since it was previously botched by a past owner.
The Noise: Does that sucking sound point toward a vacuum leak at the SCV or the base gasket, or is it likely just air being pulled through the carb?
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[DON]

If I remember right, there is a “weight “ under the discharge nozzle in the carb throat. I might be remembering a Holley 2300, but it should be similar system set up with different part locations . Is this the weight you are referring to? The absence of this part should not cause the leak. It still should be reinstalled.
I would do a couple checks:
Put a straight edge on the pump cover and the mating surface on the carb. You can buy a new cover but they are pretty stout, probably not warped, but needs to be checked.
The next thing is make are the accelerator pump passages aren’t blocked. Remove the pump cover and diaphragm, remove the injector nozzle and “weight” ( I would call it a check valve ). Then spray carb cleaner through it. Watch for spray coming out the other end of passages, as well as blow compressed air thru it and watch for flow.
If all clear, I would install the cover and diaphragm and check function before assembling the rest of the circuit. Narrow down where a restriction might be.

 

[Frank]

My recommendation is verify the air horn gasket is correct. This is a common problem with Carter and Rochester carbs- minor differences in design over the years, the gaskets can be very slightly different. Missing a hole here, an extra hole or slot there, etc. Over time aftermarket looses touch with this and assumes "one size fits all". I've seen a wrong gasket cause that type of odd-ball issue on these brands.

 

[frozenrabbit]

Had to download your vids to watch. That fountain of a leak looks like a full-on hole in the diaphragm, or your cover plate is broke out behind the lever arm at the top, missing weight would not cause that.

Your carb is missing the bowl vent rod and linkage arm for it.

Don't know if other forum members can see your video uploads.

 

[DON]

I could see them when I tapped on them. I agree, sure looks like a problem at the cover/diaphram

 

[witchhunter467]

Had to download your vids to watch. That fountain of a leak looks like a full-on hole in the diaphragm, or your cover plate is broke out behind the lever arm at the top, missing weight would not cause that.

Your carb is missing the bowl vent rod and linkage arm for it.

Don't know if other forum members can see your video uploads.

I already replaced the diaphragm, and other gaskets, so its not likely the diaphragm, is ended up ordering the new carb and the Weight and plate, because the carb seems like it might not have been put all back together or smth so idk if it was even a solid base

 

[DON]

ODK, be wary of the chinesium carbs. If you want , you can send me your oem carb and I will take a look at it. No charge at all , just pay for shipping

 

[witchhunter467]

ODK, be wary of the chinesium carbs. If you want , you can send me your oem carb and I will take a look at it. No charge at all , just pay for shipping

I bought the carb off of Mike's Carburetor Parts figuring that he's a known figure for carb stuff, and its based on fords replacement for the 1100 anyways, and ill think about it

 

[DON]

He should be a knowledgeable vender, I have ordered parts from him . Never any problems

 

[witchhunter467]

He should be a knowledgeable vender, I have ordered parts from him . Never any problems

Pretty much the consensus I heard online which is why I figured it would likely be a good purchase, even though theres very little documentation online outside his website

 

[mustang6]

I have ordered rebuild kits from Mike with good results, but haven’t had to call him for support. In this case would call him and send him your videos. Like Don said, I don’t even know where that fuel that is spraying up is coming from. If it was coming out of an open vent I would say something is blocked or leaking internally but when it’s spraying up out of that diaphragm area where there are no designed pathways to the outside, it means the diaphragm itself is split or the cover or something nearby isn’t sealing. A closeup picture of that area would help even us understand that better. As was also mentioned above, I don’t like that your main vent appears to be missing a rod (and is plugged?), although I have seen rebuilt carbs come that way out of the box.

 

[witchhunter467]

I have ordered rebuild kits from Mike with good results, but haven’t had to call him for support. In this case would call him and send him your videos. Like Don said, I don’t even know where that fuel that is spraying up is coming from. If it was coming out of an open vent I would say something is blocked or leaking internally but when it’s spraying up out of that diaphragm area where there are no designed pathways to the outside, it means the diaphragm itself is split or the cover or something nearby isn’t sealing. A closeup picture of that area would help even us understand that better. As was also mentioned above, I don’t like that your main vent appears to be missing a rod (and is plugged?), although I have seen rebuilt carbs come that way out of the box.

I got the new carb installed the other day, and it seems to be running good, but for whatever reason the idle is almost bottomed out, and it still feels like the idle is low, like I feel like i need to pull the choke out a small amount just to raise it when im in gear but stopped, in neutral its fine with the choke in and idling, and driving seems fine, but in gear idling like at a stop sign, it wants to drop low, I threw on a tach last night and drove it around a little bit, and it needs brakes and somethings rattling in the back, but it seems to drive fine, atleast 0-30 and when parked the tack reads about 800 idle rpm idk where it should be, and i cant remember what it was it in gear idling because I did as I said and pulled the choke out a tiny bit since it felt like I would stall otherwise, I can do more testing later and plan to get an o2 bung welded on tomorrow and than figure out an afr gauge so I can adjust the mixture, but I would think the idle screws wouldnt need to be bottomed out for it to idle fine? It wanted to drop like 500 or lower I think before I pulled the choke

 

[alwill923]

IMO get rid of the SCV carb and dizzy.