my first carb rebuild, done, but adjustment question

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1969dodgedartgt

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hey guys,
I just successfully rebuilt my carter bbd 1 1/4" solid fuel carburetor. All went well but I was a bit confused with some of the adjustment settings and it seems this is causing a problem.

If I go from no to full throttle quickly the car is prone to die. I also had a loud bang (backfire through carb?)from the engine when doing this once.

I did not check float setting, was kinda hoping that it seemed to be ok before and still should be. The pump adjustment setting could easly be the problem because it says to adjust the untill the pump shaft is a specified distance below the dust gasket cover, but I could not find what distance this is suppose to be. Also my vacuum piston spring was missing and still is.

please let me know what I should check for this dieing on zero to full throttle problem.
Thanks and some pics.
 

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one more, also does anyone know where I can get a new idle adj screw-needle, one of mine is bent.
 

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what type of carb is it? whenever you rebiuld them I always use a straight edge to check all the parts, to see if there's no warpage.
 
OK were to start. First the most important adjustment is the fuel level because everything else works off of it. If any parts were changed or disturbed in any way with the float or needle valve or seat it will need to be redone. Basically the way it work is this-the venturi effect causes a vacuum to be formed. That vacuum draws gas by pulling it through the small passages/jets. If the float level is to high it will be easier for the gas to pull through and that is too rich. To low and it is harder and that is lean. Check the float level with the fuel bowl gasket in place. You should have a cut out gauge in the kit for that.
 
Must find the vacuum piston spring. Must have to function. It pushes up when the vacuum pulls down. It balances the piston which holds the thin brass rods that varies the air/fuel mix at different throttle positions.
 
1970PAValiant said:
what type of carb is it? whenever you rebiuld them I always use a straight edge to check all the parts, to see if there's no warpage.
Click to expand...
It is a Carter B&BD (BBD) Ball and Ball Dual. Straight edges are good but you need a flat surface to really know if it is flat or not.
 
slant6/4speed said:
OK were to start. First the most important adjustment is the fuel level because everything else works off of it. If any parts were changed or disturbed in any way with the float or needle valve or seat it will need to be redone. Basically the way it work is this-the venturi effect causes a vacuum to be formed. That vacuum draws gas by pulling it through the small passages/jets. If the float level is to high it will be easier for the gas to pull through and that is too rich. To low and it is harder and that is lean. Check the float level with the fuel bowl gasket in place. You should have a cut out gauge in the kit for that.
Click to expand...

no such gauge in the Daytona parts kit I got. I'll take apart and check dry float level, if thats what your advising.
 
slant6/4speed said:
Must find the vacuum piston spring. Must have to function. It pushes up when the vacuum pulls down. It balances the piston which holds the thin brass rods that varies the air/fuel mix at different throttle positions.
Click to expand...


:) its not like I lost it, it just wasnt in there, I can go to a hardware store and try and find something that fits/looks right. If I were gona do this, what (length,diameter, and spring constant-type thing) should I look for? perhaps I should just buy a new carb. I'm kinda just happy to have gotten the rebuild experience, if I had read more I might have learnt more about its function, I could take it out, put new one in. Then when I read I can examine the old one for reference. Hard to read the service manual I got with, without more pictures or something in front of me.

I just didnt attach the choke pull off rod at the point I took pictures. Its attached now. I thought that it was maybe running too rich and flooding at full throttle, so I tried adjusting mixture screws to no advale.

FYI she starts great and runs just dandy except for the zero to full throttle issue. Oh when I do step on gas she will give a voo-rooom with slight hesitation between voo and rooom, instead of just vrooooooom
 
1969dodgedartgt said:
:) its not like I lost it, it just wasnt in there, I can go to a hardware store and try and find something that fits/looks right. perhaps I should just buy a new carb. I'm kinda just happy to have gotten the rebuild experience, if I had read more I might have learnt more about its function, I could take it out, put new one in. Then when I read I can examine the old one for reference. Hard to read the service manual I got with, without more pictures or something in front of me.

I just didnt attach the choke pull off rod at the point I took pictures. Its attached now. I thought that it was maybe running too rich and flooding at full throttle, so I tried adjusting mixture screws to no advale.

FYI she starts great and runs just dandy except for the zero to full throttle issue.
Click to expand...

Can you take a picture of the missing spring in the drawing/instructions? Maybe its not the one you think it is.
The WOT (Wide Open Throttle) problem is one of two things-accelerator pumps stroke is to long(rich/stumble/black smoke out back) or to short (lean/stumble and back fire) or the wrong fuel level which will make it like its to long/short
 
its number 29 in the picture, looks to be below/around the piston assembly. Maybe it was still attached to the piston asmbly and I just over looked, let me check the video I made of me taking the thing apart.
Thanks
 

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....I see u dont have the front cover on all the way........u prolly have the plastic metering rod pieces out of place.....u need 2 adjust the metering rods by way of the accellerator pump ......yes u need that spring........ur pop is a lean condition.........kim.....
 
oldkimmer said:
....I see u dont have the front cover on all the way........u prolly have the plastic metering rod pieces out of place.....u need 2 adjust the metering rods by way of the accellerator pump ......yes u need that spring........ur pop is a lean condition.........kim.....
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I managed to strip the threads for that front dust cover, I took these pics before I retapped the cover screw and screwed the cover down. The (metal) [metering rod adjustment/ pump adjustment] is one I could not figure out. If its a lean problem, I can adjust the pump accordingly. I'll try this, Thanks kim


That spring was not there.... anyone know the specs for it? (i know that's unlikely)
 
usually in the summer is the best time to find 2-3 of those at swap meets. check craigslist and get a donner one, might be cheap
 
OK that is like the WCFB Carter carb. Good news is the spring can be anything that will take the slack out of the system as the metering rods are mechanically moved up/down by the horizontal rod that moves with the throttle.
 
WCFB? I'd love to get/buy a new tag for it too. (even though it's kinda old and seen better days)

The slack in the system perhaps might also be removed by a proper metering rod setting, which I think I did. The carb did seem to work fine before the rebuild.
(there is a metering rod adjustment and a pump adjustment, both of which involve the metering rods) the first I did ok, the second I could not find proper specs for.
 
slant6/4speed said:
OK that is like the WCFB Carter carb. Good news is the spring can be anything that will take the slack out of the system as the metering rods are mechanically moved up/down by the horizontal rod that moves with the throttle.
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would a picture of any particular area allow you to nail down exactly what carb this is?
 
Nooooo, it is not like a WCFB in any real way. It is a post-'76 BBD. Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download. The spring must be the correct one; "any ol' hardware store spring" will not work correctly, though it might be better than nothing as a crude get-by measure. The missing spring and bent idle mixture screw suggests this carb has been kicked around harder than one might want if one is picking a carb to rebuild. Float level is a crucial check-and-adjust point in rebuilding any carburetor, but especially a BBS or BBD with their dual/pontoon style floats. Float level needs to be checked at both pontoons and it must be accurate. Die-out on hard acceleration suggests the accelerator pump might not be working; with the engine off and the air cleaner lid removed and the choke open, peer down into the carb throat as you operate the throttle lever. You should see good, solid shots of liquid fuel each time you open the throttle.

Problems, what problems? :-(
 
Your carb is a Carter type BBD. I am saying that the metering rods are the same system that Carter used in the type WCFB (Walter (or what ever his first name is) Carter Four Barrel) the first four bbl carb back in 1952. As to which number it is I do not know. They are pretty much the same with minor changes (smog controls). The meter rod adjustment is a little tricky. Its hard to hold them down at the same time adjusting. You may look on the net to find how the wcfb was adjusted.
 
His name was Will, and no, the step-up rod system in a solid-fuel (post-'76) BBD is not the same in operation or adjustment as the step-up rod system in a WCFB.
 
I agree with Dan. Gotta have the spring for that kind of carb. Also, get another carb at least for parts. Those carbs were common on pickups vans etc. Float must be set every time you replace the needle and seat. If you cant find the measure in the kit, get one of thise small rules with the sliding depth stop on them. (harbor freight etc). The specs should be listed in the carb directions for the float adjustment. Gotta follow directions to a tee. make sure you hook-up the vacuum acccessories on the correct vacuum nipples. (distributor advance has its own "ported" source) . Oh well, its ok to do it over, thats learning. (at least those carbs are somewhat easy to find, they made tons of them)
 
oh buck, after watching this, what the manual was saying makes a lot more sense, along with what you guys/gals are saying. plus its a super cool video :)

thankfully I dont have to drive her, but I don't have time to dig up all the info I need to be a carb expert either. Before I did this rebuild, someone on here correctly told me that it would probably more effective monetarily to just buy a new carb, but then I might not be learning what I'm learning now. My car is a tool and a toy, I'm enjoying working on and learning from it. I dont have the time or patience to figure it all out without the appropriate motivation/need, like messing up on a rebuild and finding out what I did wrong and why it's wrong. Its a learning process. I dont want to waste your time either but I personally like to help people who know less than me in areas I feel I can help, and am very thankful for FABO providing an environment where there are helpful people like you guys that may do the same for me. No its not the ideal environment for that but it has worked well for me so far (knock on wood). I'm very grateful for all your advice even if its not all entirely correct or complete.


I did not replace the needle, but I did replace the seat so I will have to look at float level. The new kit did not come with a new needle.

time to check some work email and sleep, I'll keep ya posted.

Creed
 
You need a new needle and seat. If the kit did not come with a new needle, it was incomplete. The needle is a wear part.
 
It is a learning process indeed. None of us is born able to overhaul a BBD (BBS, WW3, Thermo-Quad, 1920, 2280, whatever) in 45 minutes without looking at any references. That takes many years and many carburetors worth of experience. Don't get discouraged that you didn't clang it 100% the first time through. I can't recall, whose kit did you use? New idle needles can be had from Walker -- possibly new step-up piston spring, too; would need to look. Can't do it right now, I just finished writing up a giant report on the Detroit auto show (on deadline) and my eyes are all crossed up.
 
slantsixdan said:
You need a new needle and seat. If the kit did not come with a new needle, it was incomplete. The needle is a wear part.
Click to expand...


recall I got a Daytona kit on your recommendation. it cam with a ball-baring type thing inside the seat instead of a needle. which makes me recall that the seat did not get replaced either, so the float settings should be exactly as they were before the rebuild
 
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