Rebuilding a carb difficulty? D.I.Y or leave to the pros?

Discussion in 'Carter' started by miels, Aug 4, 2010.

  1. miels

    miels Well-Known Member

    I have a 65 riviera and i believe the original carb. Although I haven't checked numbers yet according to teambuicks references its a carter afb? When i bought the car we bypassed the gas tank and ran directly to the carb from a gas can. This car was sitting for some 15 years started and moved across the yard to another garage, and then sat for another 5yrs.

    I don't know much about carbs but i do know its not moving freely. The doors on it don't move much and from what i remember they are supposed to open freely and when I was troubleshooting this spring i was told i should see gas shooting into the carb while looking down and i didn't?? Its a bit weird to me cause during this momumental snowstorm this winter i had the car running on its own power trying to move it outta 20" of snow into a garage. This spring I bypassed the tank again and ran from a gas can into a new fuel pump and filter (i didn''t have an electric pump direct to carb like previous owner) it wouldn't start on its own power. It did sputter for moments when pouring gas directly into it, but that was the extent of it starting.

    Now that I have time this summer i thought to just rebuild the carb. or have it rebuilt... I have been reading what I can gleam from a search and what i find mostly is to stay with the original instead of buying a new edelbrock?

    And lastly there is a shop in town that rebuilds carbs. They quoted me $225Is it difficult to do myself or a job better left to pros? I need to get it moving on its own power in and out of this garage.
  2. doc

    doc Well-Known Member

    Dont pay $225 for a rebuild ...... The main thing that you dont want to happen is for the butterflys to seize up.... oil and operate them occasionally.....
    The kit and instructions are available and this carb is among the simplest to rebuild.... I just use lacuer thinner to soak them in when I rebuild them and then blow them out with compressed air....
    You can do it yourself and save a ton of money.....:Smarty:
  3. miels

    miels Well-Known Member

    Thanks DOC... but what if you need new floats, and needles and what-cha-ma-call-its? All the post and problems i've I been reading is like greek to me. How will i know whats needed if its bad etc? And how do i get it sparkling clean like the new or rebuilt ones? Does the laquer thinner do this? Do you just take the entire carb and put in in a container of laquer thinner?

    I'm excitied to do the job now. Does the kit come with the correct directions? or will i need to purchase a separate book?

    Thank you for saving me some money that can go to another part of the project
  4. doc

    doc Well-Known Member

    When you take the carb apart, you can inspect all that ,,, the floats are hollow and made of brass... not much can go wrong with them... they can get a pin hole in them and fill up with fuel... but in 40 years , I have seen exactly 2 like that... not much chance of that happening.... on the afb try spraying some alluminum wheel cleaner on the carb body and top , after it is disassembled and cleaned...
    Lacquer thinner is not the best cleaner out there the regular carb cleaner is,,, but the last time I priced it ,,,, it was a very expensive item....
    all that stuff is flamable ,,, so be very carefull using it....
    a carb is not hard to disassemble ,just be sure you have all the screws out before removing parts... and dont force any thing much at all... if some wont come loose , stop and start hunting for screws....
    every thing you need to do the rebuild will come in the kit along with instructions.... you will need needle nose pliers, a large straight blade screw driver, a phillips screw driver, and a gasket scraper.... plus a metal container to hold the carb parts,,,, 1 gal of cheap lac thinner.... and a small brush to brush clean parts...
    make drawings, take pictures , ect to make sure you get stuff right going back....
  5. Cliff R

    Cliff R Well-Known Member

    I agree that the AFB is among the simplest of carburetors to rebuild, but we still lots of problems with folks doing them at home.

    Some of the problems they have are not their fault. Ethanol is in all the fuels now, and nothing rubber will live inside your carburetor much longer than it took me to type this.

    There are still a LOT of old stock kits in circulation that do NOT contain parts that will hold up in this fuel. Never "assume" the kit you bought contains upgraded components that will survive in modern fuel blends.

    We only recently tested (for the manufacturer) some new style accellerator pumps that were upgraded for ethanol. They (our supplier) actually stopped production for a while of 4GC, 2GC, AFB, AVS and Thermoquad pumps due to problems with ethanol.

    We had been upgrading our Q-jet pumps using custom components for almost 2 years now, as the "blue" seals on those pumps were NOT ethanol compatable, and there was no collar crimped on the pump body to keep the shaft from pulling out of it. We just got the latest version in a few weeks ago with all the upgrades included.

    Where most folks fall short in home rebuilds in not pressure testing the castings and correcting any leaks in the main casting. Although rare with AFB carbs compared to other models, they can still leak. The accellerator pump system, specifically any inlet check balls are another BIG problem area with many models. If the check ball leaks, all the fuel that's supposed to go in the engine when the pump compresses, goes back to the fuel bowl instead. The carb doesn't work correctly when placed in service, the builder takes it apart, often many times, can't find a problem anyplace, and gives Edelbrock a big wad of money for a far inferior replacment, when it would have taken seconds to fix the one he had in front of him.

    Another big problem is getting all the crud out, especially in idle tubes and very small orifices. Drying up cycles leave considerable "varnish" behind over the years. Very few solvents will get into tiny areas and get it all out. We recomend obtaining precision drill bits and hand sizes every single orifice in the carburetor related to fuel and air delivery (idle tubes, idle airbleeds, etc.) No need to enlarge any of them, just size them and at the same time clear/clean them of any obstructions.

    Needle/seat assemblies MUST be vacuum/pressure tested, and the float set correctly. Many will NOT pass a vacuum/pressure test right out of the package. Minor imperfections under the seats or on the gaskets will also cause a fuel leak and flooding, so test the outside of the seats as well as where the needle seals them off.

    Last on the list of basic issues is worn jets and metering rods. Yes, about 80 percent will NOT pass a pin gauge measurement and metering rods will often be worn some.

    These parts are available, but difficult to obtain. If not within specification, your freshly rebuilt carburetor will NOT work correctly as far as fuel delivery to the engine across the load/speed range.

    The best way to make sure your home build is successful, is to arm yourself with accurate information, and good parts. You will also have to make basic settings during the build, and fine tuning once placed in service......Cliff

    IMHO, $225 is a very fair price, IF you are getting a complete/correct rebuild with modern components. It should incude a running test (highly unlikely) and all basic settings made prior to recieving the carburetor......Cliff
  6. doc

    doc Well-Known Member

    This info needs to be made into a sticky....
  7. techg8

    techg8 The BS GS

    X2 good info:TU:
  8. speedtigger

    speedtigger 9 Second Club

    Rebuilding a carb is easy. Knowing what to do when it doesn't work right when you are done is a whole other story.

    If you like tinkering and reading and solving problems then have at it and have fun. If not. I say have a pro rebuild it.
  9. JZRIV

    JZRIV Platinum Level Contributor

    Excellent info from Cliff R. It is dead on. I'll add one more item that is commonly overlooked by the do-it-your-selfer. Too much play between the throttle shafts and housing will create vacuum leaks and the carb will never work right. You might get lucky installing a simple kit and having it work but if you want it done so it performs like new, have it professionally rebuilt. Many people have no idea they are loosing performance because the carb was not rebuilt properly. Sure the car will run but not like it should. $225 is a resonable price to have it done right with all the Ts crossed and Is dotted as Cliff R mentioned.

    If you want another option for a professional rebuild, contact Tom Telesco known as Telriv here on the board. He rebuilt mine and that included a real life functional test on an engine.
  10. Cliff R

    Cliff R Well-Known Member

    Perfect timing as I had a good friend bring a 1967 Pontiac AFB to the shop late last week. It had just been "rebuilt" by the cars owner and a couple of friends, and wasn't working.

    It was a MESS. Heavy varnish and build up in the float bowls, and black carbon deposits on the throttle bores, etc. It took half a day in the ultrasonic cleaner to get it cleaned up.

    They installed a kit with a leather pump seal, which had already failed miserably.

    The accl pump feed checkball was leaking most, if not all of the fuel back into the bowl.

    Both main metering rods were bent, as them must have tried to put the top in place with the metering rods and power pistons alreay in the top section.:Dou:

    Neither float was adjusted correctly.

    The idle tubes were plugged with varnish and debris.

    The secondary boosters were installed on the wrong sides, and with the wrong gaskets under them.

    The accellerator pump check ball was not sealing in the casting.

    The choke pull-off piston was sticking badly in it's bore, and the seal under the housing was bad, and not replaced when they did the "rebuild".

    Pretty common mistakes, and problems we see associated with these units.

    We charged the customer $250 to completely and correctly rebuild the AFB, and he couldn't be happier with it......Cliff
  11. miels

    miels Well-Known Member

    Thank you Cliff and everyone for your help and responses. I just wish i would have had this information before I tore into the carb... 225 or 250 isn't much to avoid a major headache....

    Please see my new post

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