Help / Carter 4615S Will Not Idle

[Gripper]

1. 1969 Super Bee with 383 Carter 4615S will not idle below 1500 RPMs engine dies because of lack of fuel if you pump throttle it will pick back up and run until RPMs drop back off or you squirt gas down carb to keep running.
If you open idle screws 7 to 8 turns open it barely tries to idle but still quits.
Engine runs fine above 1500 to full throttle position.
I have disassembled carb 2 times cleaned and blew out all passages and never found anything wrong. ( I am not a Carter expert by any means )
2. I installed a Street Demon 625 from another car to see if carb was the problem or some else was wrong.
Engine started right up and idled down to 700 to 800 smooth and steady no problem.
This proves to me the Carter has a problem with it not engine, ignition ect.
I do not know how to get the idle circuit to work ?
3. Any help or ideas ?
If you need more pictures or information let me know.

Thanks Gripper

 

[RJRENTON]

1. 1969 Super Bee with 383 Carter 4615S will not idle below 1500 RPMs engine dies because of lack of fuel if you pump throttle it will pick back up and run until RPMs drop back off or you squirt gas down carb to keep running.
If you open idle screws 7 to 8 turns open it barely tries to idle but still quits.
Engine runs fine above 1500 to full throttle position.
I have disassembled carb 2 times cleaned and blew out all passages and never found anything wrong. ( I am not a Carter expert by any means )
2. I installed a Street Demon 625 from another car to see if carb was the problem or some else was wrong.
Engine started right up and idled down to 700 to 800 smooth and steady no problem.
This proves to me the Carter has a problem with it not engine, ignition ect.
I do not know how to get the idle circuit to work ?
3. Any help or ideas ?
If you need more pictures or information let me know.

Thanks Gripper

View attachment 1699960

IMO....ALL idle fuel originates in the primary booster venturii assemblies. Are you sure the 0.035" diameter idle fuel tube is clear. Likewise, all the idle fuel transfer passages are clear. These begin where the booster venturii assembly attach to the body and have the correct gaskets in place? The mixture then travels horizontally than down to the idle mixture fuel channels to the mixture screws to the throttle bores. Make sure all passages in the booster venturii assemblies are clear....the metering orifices are very small. PM me if you need more help....
BOB RENTON

Pix of typical AFB.....AVS SIMILAR

 

[WileE]

Evidently the problem exists, as stated, in your idle circuit, since the main metering circuit functions fine once you get the rpm above idle. Clean and clear is the keywords for the idle circuit passage, whether it's gasket material, dirt, etc.

 

[Don Frelier]

The primary venturi cluster(s) are likely the problem.
Something is blocking the passages in there.

Do you know the primary jet size and which metering rods are installed?

 

[pnora]

Make sure you have the correct base gasket and that it is sealing properly.

 

[Kern Dog]

Evidently the problem exists, as stated, in your idle circuit, since the main metering circuit functions fine once you get the rpm above idle. Clean and clear is the keywords for the idle circuit passage, whether it's gasket material, dirt, etc.

The primary venturi cluster(s) are likely the problem.
Something is blocking the passages in there.

Do you know the primary jet size and which metering rods are installed?

Years ago I had a carburetor from a 71 Chrysler 300. I had it rebuilt by a local shop to use on a 440 I had in a truck. It too wouldn't idle. I had to crank the curb idle screw up to around 1800+ to keep it running. I had it rebuilt a second time. The man made mention of some passage that had a check ball in it, the ball was stuck while some gel-like substance had it "glued" in place and it didn't dissolve in the tank when the carb was apart.
I don't know the mechanics of the Carter carburetors but what he said made sense to me.
Good luck.

 

[Gripper]

Thanks for the help support ideas.
I will remove carburetor tomorrow morning and get back with findings.

Thanks Gripper

 

[Rishi]

If you open idle screws 7 to 8 turns open it barely tries to idle but still quits.

View attachment 1699960

you say "idle screws"? There is technically only one "idle speed" screw and it's facing forward on the pump side at the throttle lever. Funny thing, though, you said "screws" and you show an image of the idle MIXTURE screws.

Which ones are we talking about? The idle Mixture screws and the idle Speed screw behave differently.

To set the engine (curb) idle RPM speed, you use the single "idle speed" screw on the pump-side of the carburetor, pressing slightly on the primary throttle shaft lever.

When fiddling with the air/fuel idle mixture (in use during engine idle) there is a procedure for turning the mixture screws to achieve a peak in engine idle RPM. But the procedure includes correcting the idle RPM using the other single "idle speed" screw.

The carburetor in your image looks really clean. Maybe it works fine, and the idle mixture got out of whack attempting to change the idle speed? Or are you attempting to set the idle mixture? If so, 7-8 full turns from fully seated starting point seems much greater than the last few I have counted on a rebuild.

 

[Orig69]

1. 1969 Super Bee with 383 Carter 4615S will not idle below 1500 RPMs engine dies because of lack of fuel if you pump throttle it will pick back up and run until RPMs drop back off or you squirt gas down carb to keep running.
If you open idle screws 7 to 8 turns open it barely tries to idle but still quits.
Engine runs fine above 1500 to full throttle position.
I have disassembled carb 2 times cleaned and blew out all passages and never found anything wrong. ( I am not a Carter expert by any means )
2. I installed a Street Demon 625 from another car to see if carb was the problem or some else was wrong.
Engine started right up and idled down to 700 to 800 smooth and steady no problem.
This proves to me the Carter has a problem with it not engine, ignition ect.
I do not know how to get the idle circuit to work ?
3. Any help or ideas ?
If you need more pictures or information let me know.

Thanks Gripper

View attachment 1699960

It could help to have more pictures of both sides, the rear and the top of the carburetor.

 

[4speed68rt]

Take it apart and clean it out. It probably has some dirt or something in it that is clogging something up. Even when they look clean on the outside, inside can be full of fine particles or gooey jellified gas from sitting too long. Sometimes they get a red looking dust from the gas all evaporating. Sometimes a small piece of gasket or rubber is covering a small hole. You just have to take it apart and see whats making it not work. The guys above gave some good places to start looking.

 

[Gripper]

Took carb apart cleaned and blew out everything.
The biggest problem i found with carb is all 4 throttle shaft bushings are badly worn out.
I put carb back on and the engine idled down but was not running smoothly.
I sprayed carb cleaner on all 4 bushings while running and all 4 sped up engine speed.
Checking on sending carb out for replacement of bushings.

Thanks Gripper