I asked this question in the "Bench" section but the answers were not specific enough for me. My engine is a '65 300 high comperssion. I carefully disassembled my carb to rebuild it keeping right side parts from left side parts. All of a sudden a little stainless steel BB appeared on my bench. I think it came from below the fuel nozzles but I am not sure. My chassis manual is no help and the exploded diagram that came with the kit doesn't show the BB. I assume it is some kind of check ball. The interesting thing is that the kit did include a new BB!!! Where exactly does this go? A picture or diagram would be very helpful. As I stated on the "Bench", I am not a mechanic although I do play one in my garage. Any help would be appreciated. In reading other posts here I see that electric chokes are not recommended for these cars (I live near Seattle and the car is an automatic). I thought electric chokes were a popular conversion. If it isn't a good idea, why not? Not questioning the wisdom, just looking for enlightenment. Thanks. Greg
The only ball that I know of is the one in the bottom of the accelerator pump well....but that one is pressed into a brass plug. see if it's still there. There is another check valve located under the 2-nozzle squirter that sits between the front barrels. But it looks more like a 'needle' from the needle/seat at the float. But maybe some carbs used a ball? BTW, this was just discussed recently (somewhere here), with the same conclusions...
I saw your other post last week and reflexively replied to it the same as the others did -- pump check valve, just drop it in. Then I thought a little and checked the service manual, diagrams didn't show it like I pictured it in my head. The pump inlet check valve is a brass assembly about the size of the jets. I must have been thinking of the Q-jet or 4GC. I deleted my post 'cause I hate giving wrong info. I just bought 2 '65 AFB's off Ebay that UPS says will be delivered this Monday. I don't know what's inside them so I will be rebuilding and will post what I find. My memory from several AFB rebuilds I've done says that you don't need it. I don't know why it was in your carb. I think some of the mid-50's Buicks with gas pedal start had a balll check valve for that system and maybe (I'm guessing) that's why its in the kito No: . I hope you can wait a few days for a better answer. (By the way, I play a mechanic in my garage too!)
No hurry at all. It might be years before the 4 door sees the road again. I know what you are referring to about the check ball that is encased in a brass fitting that looks like a jet at the base of the accellerator pump. It is not this fitting. I suspect it goes under the fuel nozzles to prevent the pump from sucking air when operated. I further suspect that later (or earlier) versions of the AFB use a needlelike brass piece to do the same thing. I find it odd that no exploded view of the Carter AFB shows the check ball, including what I found on the web. If it does go under the fuel nozzles is that the only thing that goes in there or is there a weight on top of it too? The bottom (underside) of the squirters (nozzles) has a casting that is a half circle around the hole that goes to the squirters. Is that normal or has part of the casting broken off? I suspect it is normal as when fuel is pumped to the nozzles, the check ball would rise and stop the flow (if that is where the check ball goes). The car is an original 4 BBL engine but someone installed a bojacked Edelbrock carb with too big of jets, no choke, and a cobbled together linkage that disconnected the kickdown switch. The carb I am rebuilding is correct for the engine. I have little experience rebuilding carbs but being how this is going into a 4 door driver, I don't want to spend $400 having the carb restored. A final question do these AFBs have a problem with worn bushings at the throttle shafts? I'd hate to invest a lot of time in something that may have a vacuum leak. Inquiring minds want to know. I am grateful to get your feedback. When I first posted my question I posted it on the "Bench" as I didn't see any posts here newer than 6 months. I guess there are people who brouse the entire forum. Thanks again. Greg
Jon (Carb King) posted this about the throttle shafts: >>>The factory design tolerances on the AFB were 0.016~0.022 inches. This is necessary due to the expansion of the large bearing surface area on the AFB. Too tight a clearance will cause binding when the engine is hot. Conversely, the factory tolerances on the Q-Jet are 0.004~0.006 and bushings should be installed at 0.010.<<<< Accelerator pump squirters: The bottom is flat except for the half-round protrusion....so yours is ok! I've had a few '65 carbs apart lately...a 3921 (401) and a pair for the 2x4 setup...they all use the brass 'needle' for the acc pump. You might want to PM 'carb king' to ask about the check ball. I don't recall seeing it on any of my AFB's. The best deal I've found for a rebuild kit is the Hygrade #283D from www.rockauto.com ...about $17! And for rebuild instructions, I prefer the Buick Service manual...in addition to model-specific specs, it also explains the theory in how the different systems work. Good Luck!
Devon, I did finally find a copy of the diagram you posted but it made no sense to me. It shows the 3 pieces installing from the bottom of the carb. I have nothing that installs from the bottom. I think the diagram is a convoluted attempt to make the drawing less cluttered and depicts the captured check ball that is installed in a brass fitting at the base of the pump (discussed in one of the previous postings) which actually installs into the float chamber. I am thinking that the check ball is an early version of the needle valve that is installed under the fuel nozzles. I am not sure if that is all that is installed there or if there is something that sits on top of the check ball as a weight. If anyone knows, I'd appreciate the info. Also if the needle valve is a replacement for the check ball and it works better, can I change it over? I am not at home right now so I don't remember if the rebuild kit came with both the needle valve and the check valve. I'll check it out this evening when I get home from camping. Greg Greg
Walt, Thanks for the information. I did not disassemble the throttle shafts to measure them. As the screws are peened over to secure the throttle plates I didn't want to mess with reinstalling them. I did soak the disaaembled carb overnight in carb cleaner and then blew out all the passages. The only carbs I have rebuilt are 2 bbls and they fit right into the gallon can. The AFB is huge and I had to get a bigger container to get it submerged. I guess the best way to find out now is to reassemble the carb and see if I have a vacuum leak at the shafts. What I was asking is if this is common with the AFB or what should I expect. I know it is a hard question to answer. I did use the chassis manual (shop manual?) for specs and general information and I did find it somewhat useful. I was surprised that it didn't include an exploded diagram. The pictures of the linkage are very helpful in reinstalling it. I also took several pictures of the fully assembled carb prior to disassembly with my digital camera in case I needed further help remembering how it looked all together. Thanks. Greg
Hey Greg I didn't forget you. I got my Ebay carbs. They are factory dual quad carbs, just not in as good shape as I had hoped. Some one who definately only plays a mechanic has been inside them before me! There is no place for a separate ball check valve in either of these carbs. If some one held a gun to my head and forced me to answer, I would say that the ball is in the rebuild kit to replace the one in the exploded view posted by Devon (DaWildcat) above. A change to an integrated assembly would make sense from a production standpoint. Why was there one in your carb? o No: You never know who worked on it before you. I found a float needle in the passage under the thermostatic valve assembly on the rear carb I just got, and several other "improvements" uzzled: . The brass check valve under the squirter just drops in pointy side down, no spring or weight on top of it. I think you'll probably be better off not futzing with the throttle shafts. The AFB is not known to have a wear problem here like the Q-jet does. Re: your question on the choke. I'm a fan of making sure the original system works the way it was designed. When these cars were new, they started and ran fine in all 4 seasons (you only get 2 in WA right -- warm rain and cold rain). Many people don't understand chokes, and disconnect it, or say it's not needed, I don't buy that. I don't believe that an electric choke is an improvement, but can work fine. Make sure everything in the original system works and you'll be OK. Let us know how it works out. I'm betting it'll run like a champ. :TU:
Ol' Yeller---I have a '65 special with the same engine and am VERY familiar with the exact carb you have. It should have the brass needle under the accelerator squirter assembly--if it had a ball (bb) in there, someone lost the needle and put that in place of it at sometime in the past. Without the correct needle in there, it will dribble fuel out of the squirters when you first hit the accelerator instead of giving a stong, clean squirt like it should. It in effect makes the accelerator pump build up to the amount of pressure it takes to lift that needle before anything squirts out. If you can't find one, I think I have an extra I can send you.
Kevin & Brian, thanks for your input. I think there was the brass needle in my rebuild kit. I guess I'll just install it and hope for the best. I'm also thinking I'll restore the original choke and reinstall it too. I still haven't heard from carbking although I did send a PM. I guess he has a life outside this forum like the rest of us!! I'll let you know how it all turns out in a week or so. Greg
Here's the update. I installed the rebuilt AFB carb today and it ran almost perfectly. I have some minor issues setting up the choke but I am confidant I can work through them. The rebuilt carb idles smoothly and no bog like the overjetted Edelbrock had. The secondaries open as they should with smooth power despite the fact that I didn't have the kick down switch connected. I did replace the filter and fuel lines before I installed the rebuilt carb. Thanks everyone for your help and suggestions. As an aside, is the old Edelbrock worth anything as a core (maybe on Ebay)? It came with a massive spacer that raised the carb up at least an inch off the manifold. I have tried 3 times now to use these carbs on different (65 Skylark) cars and have never gotten one to work properly. This last one was screwed up by a previous repairman. The linkages never seem to work with the switch pitch. One mans rant, sorry. Greg
