63 AFB problems
Thread Starter
Intermediate
Joined: Dec 2005
Posts: 41
Likes: 0
From: Roundup Montana
63 AFB problems
I am new to the forum as of today. I have a 63 340hp coupe that always has to have the accelerator pumped a bunch to start. The carb has been rebuilt in the past but the starting problem still exists. I need to know the name of a reputable carb rebuilder to send it to. Anybody know one?
Racer
Joined: Dec 2005
Posts: 428
Likes: 0
From: Boca Raton FL
Originally Posted by T&MRanch
I am new to the forum as of today. I have a 63 340hp coupe that always has to have the accelerator pumped a bunch to start. The carb has been rebuilt in the past but the starting problem still exists. I need to know the name of a reputable carb rebuilder to send it to. Anybody know one?
Le Mans Master
Joined: Jul 2001
Posts: 8,071
Likes: 317
From: Central Florida
The Carter AFB 3461 carbs are very hard to start if they have been sitting for more then one day. I have had the same problem for years and found the best and fastest solution is to buy a can of QUICK START, remove the cleaner and give it a shot....then start it up...works everytime.... Of course your choke is another problem area because it depends upon the hot air from the exhaust manifold going up into the choke area heating a cooper coil to adjust the carb when it gets warm.... The method I told you works the best.... 
Last edited by 1KULC7; Dec 30, 2005 at 10:02 PM.
Le Mans Master
Joined: Jul 2001
Posts: 8,071
Likes: 317
From: Central Florida
Originally Posted by Velocity Steve
Doesn't that engine have a Holley carb?
Only the Carter AFBs and WCFB were used...now I hope I have this right: the 250 HP used the WCFB 3501S and Auto WCFB 3500S, the 300HP used AFB 3461S and the Auto AFB 3460S, and the 340 used 3461S....The Holley was not used until 1965 on the 350 HP and above, then by 66 all carbs were Holleys... I HOPE I AM RIGHT....
Racer
Joined: Aug 2003
Posts: 404
Likes: 0
From: Sitka Alaska
Originally Posted by EBVette
The 63 does NOT have any Holley carbs..
Only the Carter AFBs and WCFB were used...now I hope I have this right: the 250 HP used the WCFB 3501S and Auto WCFB 3500S, the 300HP used AFB 3461S and the Auto AFB 3460S, and the 340 used 3461S....The Holley was not used until 1965 on the 350 HP and above, then by 66 all carbs were Holleys... I HOPE I AM RIGHT....
Only the Carter AFBs and WCFB were used...now I hope I have this right: the 250 HP used the WCFB 3501S and Auto WCFB 3500S, the 300HP used AFB 3461S and the Auto AFB 3460S, and the 340 used 3461S....The Holley was not used until 1965 on the 350 HP and above, then by 66 all carbs were Holleys... I HOPE I AM RIGHT....
EVERGREEN
Race Director
Joined: Mar 2001
Posts: 14,634
Likes: 4,684
From: Mustang OK
2026 Corvette of the Year Finalist - Modified
2025 c1 of the Year - Modified Winner
2024 C1 of the Year Finalist - Modified
2023 C1 of the Year Finalist - Modified
2015 C1 of the Year Finalist
The 64 365hp/327 had a Holley.
Instructor
Joined: Nov 2004
Posts: 110
Likes: 2
From: Portland Oregon
Hard starting Carter
According to my little Black Book the '63 340hp man. trans. had a Carter 3461.
According to the book my '64 300hp man. trans. has a Carter 3721,
which it does.
I have to disagree
that all all Carters are hard starting after they've sat a while. My car has been in the family since new, in '64, and up until recently it always started first crank after one pump of the throttle.
I used to be able to brag to friends how well it started. But not anymore. Nowadays it's pump, pump, pump, crank, crank, crank, pump, pump, pump, crank, crank, pump, crank, vroooom.
Haven't figured out what's changed but it's all stock and nothing is different other than a home done carb rebuild. I'm thinking accelerator pump or float adjustments.
Good luck, I'll be anxious to see the feedback on this one.
According to the book my '64 300hp man. trans. has a Carter 3721,
which it does.
I have to disagree
that all all Carters are hard starting after they've sat a while. My car has been in the family since new, in '64, and up until recently it always started first crank after one pump of the throttle.I used to be able to brag to friends how well it started. But not anymore. Nowadays it's pump, pump, pump, crank, crank, crank, pump, pump, pump, crank, crank, pump, crank, vroooom.
Haven't figured out what's changed but it's all stock and nothing is different other than a home done carb rebuild. I'm thinking accelerator pump or float adjustments.
Good luck, I'll be anxious to see the feedback on this one.
Instructor
Joined: Nov 2004
Posts: 110
Likes: 2
From: Portland Oregon
Hard starting Carter
We still haven't answered your question about a reputable carb rebuilder have we. Unfortunately I can't help with that one, 
but my 11 year old son just reminded me that I did have my hard starting problem significantly improved, there for awhile at least. What I had found and since forgot, until my little navigator reminded me, was that the choke was hanging up and staying slightly open. Loosening the three choke housing screws slightly, allowed the choke to operate smoothly and shut properly.
I think I need to recheck that one myself.
but my 11 year old son just reminded me that I did have my hard starting problem significantly improved, there for awhile at least. What I had found and since forgot, until my little navigator reminded me, was that the choke was hanging up and staying slightly open. Loosening the three choke housing screws slightly, allowed the choke to operate smoothly and shut properly. I think I need to recheck that one myself.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Team Owner
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
Originally Posted by daytonablue64
According to my little Black Book the '63 340hp man. trans. had a Carter 3461.
According to the book my '64 300hp man. trans. has a Carter 3721,
which it does.
I have to disagree that all all Carters are hard starting after they've sat a while. My car has been in the family since new, in '64, and up until recently it always started first crank after one pump of the throttle.
I used to be able to brag to friends how well it started. But not anymore. Nowadays it's pump, pump, pump, crank, crank, crank, pump, pump, pump, crank, crank, pump, crank, vroooom.
Haven't figured out what's changed but it's all stock and nothing is different other than a home done carb rebuild. I'm thinking accelerator pump or float adjustments.
Good luck, I'll be anxious to see the feedback on this one.
According to the book my '64 300hp man. trans. has a Carter 3721,
which it does.
I have to disagree
that all all Carters are hard starting after they've sat a while. My car has been in the family since new, in '64, and up until recently it always started first crank after one pump of the throttle.I used to be able to brag to friends how well it started. But not anymore. Nowadays it's pump, pump, pump, crank, crank, crank, pump, pump, pump, crank, crank, pump, crank, vroooom.
Haven't figured out what's changed but it's all stock and nothing is different other than a home done carb rebuild. I'm thinking accelerator pump or float adjustments.
Good luck, I'll be anxious to see the feedback on this one.
There are a lot of complaints about the AFB being hard to start after they sit unused for maybe a week or so. The problem apppears that the fuel is evaporating out of the bowl. Carter WCFB's and Holley's don't seem to have as severe a problem with fuel evaporation.
Before you start your car next time after an extended period of non-use, pop the air cleaner and work the throttle. If you see gas squirting, your bowl still has fuel in it and it should start. If you see no fuel squirting, crank your engine over maybe ten times and then hit the throttle. If it squirts fuel, you can assume the fuel is evaporating out of the bowl. If it does not squirt fuel, crank the engine another five revolutions or so and try again. If still no fuel you can assume your carb needs work or your tank needs gas in it.
I have cars with the WCFB, AFB and Holley. The AFB is the worst of the bunch with the hard start symptom. Some say aviation gas doesn't evaporate as fast as road fuel. I don't know. I doubt a rebuild will help any unless you have something mechanically wrong with your carb. An electric fuel pump will band-aid your problem if you desire to go to that much trouble.
Le Mans Master
Joined: Apr 2004
Posts: 7,106
Likes: 38
From: Newark DE
Originally Posted by T&MRanch
I am new to the forum as of today. I have a 63 340hp coupe that always has to have the accelerator pumped a bunch to start. The carb has been rebuilt in the past but the starting problem still exists. I need to know the name of a reputable carb rebuilder to send it to. Anybody know one?
Thread Starter
Intermediate
Joined: Dec 2005
Posts: 41
Likes: 0
From: Roundup Montana
Thanks for all the replies. I have owned this 63 coupe since 1975 and have always had the problem with starting. The carb has been rebuilt 3 times by different mechanics mostly for the prevention of gas leaking onto the manifold through the throttle shafts etc. The car has set for some time now and will not start until you physically pour gas down it's throat. I believe that the accelerator pump may be gone and I have always thought that the gas was evaporating out of the bowl. I have drained the gas and put in new av-gas and still have the problem.
Tech Contributor
Joined: May 2005
Posts: 15,576
Likes: 118
From: Conroe Texas
Accel Pump
One word of caution - On at least one instance, the carb kit I bought had an accelerator pump that was slightly too small in diameter, and wouldn't work. After putting the car all together I had the exact problem you describe. Swapped out the new accelerator pump for the old one and the car ran fine. Perhaps I needed to soak the new pump in light oil first as described by plaidside in your other thread.
Last edited by 62Jeff; Dec 31, 2005 at 10:48 AM.
Le Mans Master
Joined: Jun 2004
Posts: 9,016
Likes: 331
From: Southeast Missouri
Originally Posted by 62Jeff
One word of caution - On at least one instance, the carb kit I bought had an accelerator pump that was slightly too small in diameter, and wouldn't work. After putting the car all together I had the exact problem you describe. Swapped out the new accelerator pump for the old one and the car ran fine. Perhaps I needed to soak the new pump in light oil first as described by plaidside in your other thread.
I believe some of the rebuild directions from years ago used to tell you that the accelerator pump "leathers" or whatever they used had to soak up for a short period of time before they were effective.
Melting Slicks
Joined: Dec 2002
Posts: 2,257
Likes: 6
From: Mission Viejo California
Originally Posted by daytonablue64
...My car has been in the family since new, in '64, and up until recently it always started first crank after one pump of the throttle.
...Haven't figured out what's changed but it's all stock and nothing is different
Racer
Joined: Dec 2005
Posts: 428
Likes: 0
From: Boca Raton FL
Originally Posted by EBVette
The 63 does NOT have any Holley carbs..
Only the Carter AFBs and WCFB were used...now I hope I have this right: the 250 HP used the WCFB 3501S and Auto WCFB 3500S, the 300HP used AFB 3461S and the Auto AFB 3460S, and the 340 used 3461S....The Holley was not used until 1965 on the 350 HP and above, then by 66 all carbs were Holleys... I HOPE I AM RIGHT....
Only the Carter AFBs and WCFB were used...now I hope I have this right: the 250 HP used the WCFB 3501S and Auto WCFB 3500S, the 300HP used AFB 3461S and the Auto AFB 3460S, and the 340 used 3461S....The Holley was not used until 1965 on the 350 HP and above, then by 66 all carbs were Holleys... I HOPE I AM RIGHT....
