My bone stock 77 L48 has developed a stumble when I flat foot the accelerator; also the mileage has dropped considerably. Since I am a parts changer, and not a mechanic, (I never could diagnose anything), should I have the Quadrajet rebuilt or replace it? Also what would you suggest for the replacement?

If you can find a good rebuilder, go for it! Mine had the same stumble AFTER I had a friend rebuild it. Took it to my local Corvette shop and they had it rebuilt (yes, again) and put it on a flow bench. Sincce I've had it back (going on three years) its been perfect! Not even a hint of a stumble! Fast and reular idle is great and driveability is excellent! But its all in who you have do it!

I can vouch for Barrys car idle and such as it does run real well..I think you answered the question yourself..being a parts chucker is fine as long as you are very patient and have lots of money to burn..I think a real good search for that guy who can actually diagnose your car..then research the diag and parts involved and see if it is something you can tackle..since there are very few bolt on carbs that really work by just changing them it will still need some setup time..and the gas mileage drop at least for me has gotten worse in the last few months because of this corn gas we got..it has been upped to almost 8% from 4% since november..I test it every month to see what they are doing and which station will give me the best mileage..I just hope you can find someone in your area to hep out.
Rich

yostusota2011-02-14 20:15:20

Hey, another thing. You guys need to look into this stuff called Star Tron. I have to get it at a motorcycle dealer. Its a fuel additive that is supposed to cure ethanol problems. My Corvette mechanic reccomended it. He said our cars were not designed for ethanol (which they weren't). He told me if I didn't start using it eventually it would damage the seals and gaskets in the carb. Just a thought!

Get your Q-Jet rebuilt. Definitely!

I used http://www.thequadshop.net./ (The Quad Shop in Rockford, Ill.) Excellent rebuild!!

Just take yours off, send it to them and you'll get back a very nicely rebuilt Q-Jet.  You won't be disappointed. One of the folks here at C3VR referred me and I'm passing on some good info that worked for me.

Rich is right - you need to get someone to diagnose  or help you determine where the problem is first. It may be on the ignition side - timing, wires, plugs, etc... - resist the itch to just start replacing parts. Yuo can do it - it's all part of enjoying these old cars.

  Can someone go into some detail on the use of "E" fuel in these cars! Are additives required? I have a new/reman carb, do not want to melt it down into the intake.

Mark the Ethanol that is in most of the country is not supposed to be more than 10%..where I am right now its at 8%..that's the lowest I could find..really the ethanol can be bad for anything that sits...so we and small engines in boats and motorcycles are more prone to failure than a regular DD..so what do we do..for long term storage there are additives out there that should be run in..I have used the stabil brand and seems to work good on the lawn tractor..old Johnson outboard and the vette..the precations we have to take are..check and replace any rubber hose that has the slightest hint of problem..squishy comes.to mind..keep a close eye on stock diaphram style fuel pumps..as far as the gas eating your new carb in a week is false..one thing that I have been thinking about doing is put a manual shut off valve at the tank..so come winter I can shut it off and run the car out of gas..with the added stabil and removing the fuel would make for a piece of mind..I do run the race gas also mixed with 93 octane to minimize my exposure to ethanol..so really adding the stabil on long storage times would be all that is really needed.
Rich
and let the debate begin.yostusota2011-02-15 14:07:07

I had the same problem.  I had my quadrajet rebuilt and she runs like a champ!!  Get a good machanic.  Joel??  You available??  The problem is inside of the carb.  Needs to be rebuilt.  Has to do with some rubber parts and metering devices inside the carb.  Also float valve.  dskopp2011-02-15 19:41:03