OK, I give. I have been working on my Rochester 4 Jet way too much and the results have been less than satisfactory. It stumbles on acceleration especially from a stop. I had it apart at least 4 times and just can't seem to get it fixed.

So who rebuilds and or sells this carb and does it well. I've also heard the Carter WCFB is a good replacement. Any info is greatly appreciated.

Thanks in advance!

Hi Dave, Good seeing you and your car yesterday. I just saw this link yesterday evening, so this might help you.

If anybody out there is working on a Q-Jet, or will be in the future, there is a great new forum board in which questions are answered by Cliff Ruggles, a QuadraJet expert.
http://cliffshighperformance.com/simplemachinesforum/

Bill

I'm 99.9% sure that the WCFB has a smaller bolt pattern than the 4GC. A better direct replacement would be the Carter AFB, which was also available on the '57. I traded the 4GC on my '63 Riviera for an AFB a number of years ago and couldn't be happier. AFB's are all over the place and very easy to rebuild. The new Edlebrock carb is an aftermarket AFB. No one even remotely tried to reproduce the 4GC.

Jon, on this forum as Carb King, owns the Carburetor Shop in Eldon, MO. He shows a Rochester 7010070, the proper number for a '57 model 70 on his list of carbs for sale. He could rebuild yours, but he's backlogged for about three years as it is.

Bill,

Thanks for the link to Cliff's website. I have his book and it's like a bible for the Qjet.

Ed

Both the Rochester 4-GC and Carter AFB were used on 1957 Buick. Buick used the new (introduced in 1957) AFB rather than the older design WCFB.

Both the 4-GC and AFB, properly rebuilt, are excellent carburetors.

Hesitation coming off idle may be deathanol, or it may be idle mixture adjustment. Its possible that the accelerator pump is giving issues, but this is unlikely, as you have been through the unit several times.

Give me a call during telephone hours and we can discuss your issues.

Jon.

It sounds to me like it's your accelerator pump; is it leather or neoprene? It may look good, but that really doesn't mean anything, you may have done damage to it taking it apart several times, I know because I have done it myself. If it's leather you can try flaring it out a bit to make sure you're getting good pressure. Are your check-valves clean and free from schmoots, how about your venturies?
Hope this was some help,
Jaybird

I got some expert advice from the carbking and now my idle mixture is set correctly(I had it waaaaaaaaaaay rich). I do have a problem with the accelerator pump. I discovered that it is only shooting out on one side. I'm going to clean out the primary cluster next. Thanks!

Yay! Progress is a good thing.

Hmmm, one step forward, two steps back. I think this carb has it in for me. I've got the accelerator pump working great. Two nice solid streams shooting out.

Now however it's acting like it's running out of gas. I'll start it. It'll only run if I race the motor, and even then it'll quit like it's running out of gas. I figure I must have dorked up the floats somehow. Maybe they are getting stuck??

Gad!

What is the difference between a 4GC and an onion?...nobody cries when you cut up a 4GC.

Dave, like I told you Saturday the 4GC is the only carb that had me licked. I replaced mine on a 55 Century with a Carter WCFB that I cobbled from 3 junk carbs and i runs great for the first time in many years.

Willie

OK. Last night I readjusted the floats(again). I measured and adjusted with excruciatingly perfect precision. I checked everything several times.Now you know, I have done this many, many times before. I put it back together and walked away. I didn't even try it. I let it sleep.

This morning I got in the car depressed the accelerator pedal and it started on the first try. I let it warm up for about 5 minutes and then drove it. Now being the superstitious sailor that I am. I won't say anything like "IT'S FIXED!". Mind you I did not say that. It is however working great. Accelerates smoothly from a dead stop. Good power. I even stopped on my steep uphill driveway and let it run for awhile. When I pressed on the gas it climbed nice and smooth right into the garage.

Thanks for the technical help and encouragement. Like I said you didn't hear it from me, but it sure is working nice

Dave

Dave, if it acts up again take a look at the small lead wire(s) in the distributor. Over time the wire under it's insulation will fatique ( from constant movement) and may cause momentary "disconnect" when the breaker plate moves.