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PostPosted: Fri Jan 02, 2009 4:03 pm 
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Here is the Holley 1945 operation and repair manual (pdf), and here is the Chrysler training film on the Holley 1945.

Here is the Holley 1920 operation and repair manual. Discussion threads about 1920 repair are here, here, and here, and there's a big discussion thread about 1920 modification & upgrade here.

Here is the Carter BBS operation and repair manual (pdf). More-or-less-reliable specifiation and adjustment information for many BBS variants used in the US/Canada and export markets from 1960 to 1977 are here.

Here is the Carter BBD operation and repair manual (pdf)

There is a Chrysler training movie on the Holley 2280 over here.

This site has a choke and carburetor adjustment article with links to carburetor-specific information here.

Additional Chrysler-made movies related to carburetors can be found here, and more paper documentation can be found here.

Setting the idle adjustments

There's no spec for where the mixture adjustment screw should be in terms of turns in or out, so don't follow advice that starts and ends with "Set the mixture screws two and a half turns out". If you don't have an exhaust gas analyser, which most of us don't, and you're not using a ColorTune glass spark plug to set the mixture by the appearance of the combustion flame (buy one here), then the best you can do is to adjust by engine behaviour.

If you're starting with a freshly installed carburetor or the idle mixture is way off, first turn the mixture adjustment screw(s) clockwise until they lightly seat—don't turn them down tight, or you'll spoil the carburetor—and then back the mixture screw(s) out anticlockwise 2½ turns. This is not the final adjustment, it's just getting the screw(s) into a position near the right ballpark so you can find the right adjustment.

Make sure the ignition system and PCV system are all in good shape, plugs and PCV valve are clean and working correctly, ignition timing is set correctly, and valves are adjusted. Get the engine thoroughly warmed up, all the way up to full operating temperature, connect a tachometer, and then you're ready to work with the idle speed and mixture adjusting screws.

Use the curb idle speed adjusting screw (the one that doesn't seat on the fast-idle cam) to set the idle speed to between 600 and 750 rpm. Then, go round the other side of the car and adjust the mixture screw(s) clockwise ¼-turn at a time, slowly, pausing for a few seconds after each ¼-turn, until the engine just begins to drop RPM because it's too lean (you can use your ears to detect this, but watching the tachometer helps). Then, turn the mixture screw(s) back anticlockwise ¼-turn at a time or so, again working slowly and pausing, and keeping careful track of the number of ¼-turns, until the engine just barely begins to drop RPM because it's too rich. Then, you turn the mixture screw(s) clockwise half the number of quarter-turns you counted between lean fall-off and rich fall-off, and that's your final adjustment. Then re-check the idle speed and readjust to 650 rpm (use the tachometer), and you're all done setting the idle mixture and speed. You want the final adjustment of the screw(s) to be in a clockwise direction, so spring tension doesn't change the adjustment over time.

Sometimes you will not be able to find the rich dropoff point, because the carburetor is designed not to permit an overly-rich idle mixture. In that case, the best you can do without an exhaust gas analyser or ColorTune is to find the lean dropoff, then carefully back the mixture screw(s) anticlockwise just ⅛ turn at a time until the speed stops increasing (watch the tach!), then clockwise ¼ turn. Then use the idle speed adjusting screw to adjust back to between 600 and 750 rpm, and you're done.

On a carburetor with two idle mixture screws—many but not all 2bbl and 4bbl carburetors—it's important that the mixture screws be kept in sync.

Cold-engine start & stall issues

Cold-engine hard-start, stalling and rough running issues are usually choke-related; an electric choke kit is often a wise choice if your present choke thermostat is old or faulty, and the carburetor's choke pull-off may need adjusting. Choke adjustment information is here.


General advice

Always avoid "remanufactured" carburetors for the reasons discussed in this thread.

It is practically impossible to buy good quality, complete carburetor kits through normal parts-store channels any more. Spend the extra money to buy a complete kit from the likes of Don Hargrove's The Carburetor Shop; it is well worth the extra.

Problems that seem to be carburetor-related are often alleviated by doing the fuel line mod.

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Last edited by SlantSixDan on Tue Aug 13, 2024 1:08 pm, edited 14 times in total.

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PostPosted: Fri Jan 02, 2009 5:52 pm 
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Very cool. Thanks much, Dan.

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PostPosted: Fri Jan 02, 2009 9:02 pm 
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My goodness, how great is this, remind me to enter your name in the next automotive "Jeopardy" match!!


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PostPosted: Fri Jan 02, 2009 9:16 pm 
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Turbo Slant 6
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Yes thank you, I printed the whole BBD one out when you pointed me to it not too long ago. It will definatly come in handy!

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PostPosted: Fri Jan 02, 2009 9:30 pm 
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Awesome info.......! Thanks :D

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74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG


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PostPosted: Thu Jan 15, 2009 7:13 am 
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Turbo EFI
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Well the BBD videos sure were informative. And it was a pleasent surprise to see "Sam" had such a nice butt! :roll:

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'72 Duster 198 stock cam, 3:23's Hookers on jack stands for 8 years in the driveway
'79 Maxivan 360 Offy Qjet Comp RV cam/rusting in the driveway.
93 D350 160HP Cummins Auto :-( Dually Clubcab needs a injector pump
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PostPosted: Thu Jan 15, 2009 9:31 am 
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EFI Slant 6
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Dan, Thanks for posting the link for the videos.... Awesome!

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PostPosted: Wed Feb 04, 2009 8:24 am 
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Turbo EFI
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Think there would be interest in a BBD tech sticky? I have been documenting differences between Super6 and 318 BBD's with pics. Just some trial and error things I have been doing in the shop.

Let's face it there is lots of them out there, and they are cheap!

I am actually thinking about rebuilding them for extra cash. That is a while off from now. I need the proper stuff and tools to bush the shafts.

Don't know if I would be able to handle the flaming if something went wrong with somones rebuild........... :shock:

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'72 Duster 198 stock cam, 3:23's Hookers on jack stands for 8 years in the driveway
'79 Maxivan 360 Offy Qjet Comp RV cam/rusting in the driveway.
93 D350 160HP Cummins Auto :-( Dually Clubcab needs a injector pump
2005 Golden Couch Buick


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PostPosted: Wed Sep 16, 2009 1:49 pm 
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EFI Slant 6
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Location: Marquette, MI 49855 (Upper Peninsula)
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Wow, awesome information.

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1969-1/2 Dodge Super Bee A12 (440 Six Pack, 4-spd, Dana 60)
1974 Plymouth Duster 360 (4-spd, 8.75")
1973 Plymouth Duster (225, auto, 8.25")
2001 Dodge Ram 1500 QC 2wd (5.9L, auto, Dana 60)


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PostPosted: Wed Sep 16, 2009 4:23 pm 
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4 BBL ''Hyper-Pak''
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Quote:
Think there would be interest in a BBD tech sticky? I have been documenting differences between Super6 and 318 BBD's with pics. Just some trial and error things I have been doing in the shop.

Let's face it there is lots of them out there, and they are cheap!

I am actually thinking about rebuilding them for extra cash. That is a while off from now. I need the proper stuff and tools to bush the shafts.

Don't know if I would be able to handle the flaming if something went wrong with somones rebuild........... :shock:
I'd definitely be interested in a BBD sticky, I use/work on them quite a lot. I know them inside and out, but don't know the part differences between the S6 and 318 carbs. There are some differences between different 318 carbs also, and I have found that out of 3 similar appearing reman'd BBD's, I cannot make 1 decent working one. Apparently you can't mix and match base plates and bodies. So yes, I would be very interested in all BBD info you have.

I have built quite a few, and I don't think I've ever gotten one that had the shafts or shaft bores worn out enough to need repairing. I know that they do occasionally, just saying. You could start rebuilding now, and just tell them up front that if the shaft has too much wear when you receive that you can't properly repair it and they will either have to live w/ what they got, or find another base plate.

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'80 D100 SWB stepside, S6 4-spd OD


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PostPosted: Thu Sep 17, 2009 3:51 am 
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There are some differences between different 318 carbs also
Yes, there are many, many variants among Mopar BBDs, even for the same size engine.
Quote:
I have found that out of 3 similar appearing reman'd BBD's, I cannot make 1 decent working one.
See the link in the first post in this thread for why you are having trouble making "remanufactured" carburetor parts work.
Quote:
Apparently you can't mix and match base plates and bodies.
Yeah, you can.
Quote:
I have built quite a few, and I don't think I've ever gotten one that had the shafts or shaft bores worn out enough to need repairing.
Interesting. Either you're getting exceptionally low-use carbs somehow, or you're not rebushing ones that actually need it.
Quote:
just tell them up front that if the shaft has too much wear when you receive that you can't properly repair it and they will either have to live w/ what they got, or find another base plate.
Uh...or just do the job properly and get the rebush job done.

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PostPosted: Fri Sep 18, 2009 5:02 pm 
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4 BBL ''Hyper-Pak''
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So you're saying a baseplate from one carb will work on another that used a different gasket between the body and baseplate? When you buy a crb kit for a BBD, it usually has at least 2, sometimes 3 different gaskets for the baseplate. Maybe I should take pics of all my pieces and post them, see if you can can see any differences. Whatever combination I put together it will start, but then die, unless you keep pumping the gas. Rev and hold it, it will stay revved for a few secs, then try to die. Acts like it isn't pulling fuel out through the boosters.

I guess as far as rebuilding goes, rebuilding and remanfacturing are two different things in my mind. Rebuilding is simply tearing down, cleaning, replacing gaskets, needle and seats, floats, accel pumps etc. Remanufacturing would be totally dismantling, bead blasting, rebushing, polishing etc, then installing all new gaskets and stuff.

BTW are there any part numbers on the individual pieces that can help identify what version of what model?

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Rob M
'80 D100 SWB stepside, S6 4-spd OD


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PostPosted: Fri Sep 18, 2009 8:46 pm 
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Quote:
So you're saying a baseplate from one carb will work on another that used a different gasket
No, 'course not, but there are a lot of different throttle bodies that do share the same gasket and can be made to interchange without major surgery.
Quote:
Whatever combination I put together it will start, but then die, unless you keep pumping the gas. Rev and hold it, it will stay revved for a few secs, then try to die. Acts like it isn't pulling fuel out through the boosters.
Sounds like it.
Quote:
I guess as far as rebuilding goes, rebuilding and remanfacturing are two different things in my mind. Rebuilding is simply tearing down, cleaning, replacing gaskets, needle and seats, floats, accel pumps etc. Remanufacturing would be totally dismantling, bead blasting, rebushing, polishing etc, then installing all new gaskets and stuff.
It might be nice if "remanufacturing" actually worked that way, but especially with regard to carburetors, it doesn't. Many "remanufactured" carburetors can't be made to work well; see thread linked from this post
Quote:
BTW are there any part numbers on the individual pieces that can help identify what version of what model?
Unfortunately not; the casting numbers you may find can't be traced back to any particular original carb; Carter stamped the type number on a separate aluminum tag held to the carb by one of the bowl screws. Very easily broken off or lost during rebuild. :-(

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PostPosted: Tue Sep 22, 2009 10:08 am 
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4 BBL ''Hyper-Pak''
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Yeah I read the link, but mine all have clear passageways and whatnot. They just don't match up, they are like 1 old kind (w/ the skinny wire metering rods and small jets) and 2 newer ones (w/ the larger rods and same jets as AFB's). But I think even the 2 newer ones had different base plates, I need to look again. Been a while since I looked at them, and I recently found that the engine I was trying to get them to work on (S6 2bbl in my '80 D100) had a vacuum leak at the EGR valve mounting surface due to a cracked EGR. Seems like I tried them on my V8 too though, I dunno. I need to go through them again.

BTW I have a bunch of pics I took of the difference pieces in two "identical" BBD reman's, if Rug Trucker or whoever is interested in them for documentation.

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Rob M
'80 D100 SWB stepside, S6 4-spd OD


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 Post subject: carburetor
PostPosted: Tue Mar 23, 2010 5:59 am 
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TBI Slant 6
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This might be a stupid question but I am sure I have many others. *L Anyway, what exactly is the difference between remanufactured and rebuilt?

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