Comet, Cougar, Falcon, Fairlane, Mustang "Imco" Cars

Turn idle mixture screw inward until engine RPM begins to drop due to lean mixture, then turn screw outward until engine RPM increases and begins to drop due to rich mixture, finally adjust screw approximately midway between the lean and rich mixture settings. Recheck idle speed.

CARBURETOR ADJUSTMENT SPECIFICATIONS

Carter Carb. No.

Idle Speed (Engine RPM) Hot⁽¹⁾

Fast Idle (Off Engine)

Float Level Setting

Float Drop Setting

Idle Vent Setting

Unloader Setting

Auto. Choke Setting

Vacuum Break Setting

2014S
2757S
3331S
3379S.A.B
3933S

550 ⁽²⁾
475
550⁽³⁾
450-500
450-500

.054"
054"
054"
040"
.....
.040"

1/2"
1/2"
1/2"
7/16" ⁽⁶⁾
7/16" ⁽⁶⁾

.....
.....
.....
1 1/4"
1 1/4"

.....
.....
.....
.025-.030"
.....

9/32"
9/32"
9/32"
.....
1/4"

1 Lean
1 Lean
1 Lean
.....
⁽⁷⁾

..........
..........
..........
..........
..........

3934S
3402S, A, B, C
4072SA
4079S, SA
4080S, SA

450-500
⁽⁴⁾
600 ⁽⁵⁾
700 ⁽⁵⁾
600⁽⁸⁾

040"
.....
.....
030"
035"

7/16" ⁽⁶⁾
7/16" ⁽⁶⁾
7/32"
⁽⁹⁾
⁽⁹⁾

1 1/4"
1 1/4"
2 1/4"
1 3/16"
1 3/16"

.....
.025-.030"
.060"
1/16"
1/16"

1/4"
.....
.250"
.260"
.260"

⁽⁷⁾
.....
⁽⁷⁾
⁽⁷⁾
⁽⁷⁾

..........
..........
.215"
.320"
⁽¹⁴⁾
.300" ⁽¹⁵⁾

4202S.SA
4203S.SA
4367S
4368S
4373S

500
500
700⁽⁵⁾
⁽¹⁰⁾
500

.040"
.040"
.030"
.035"
.....

⁽⁹⁾
⁽⁹⁾
7/32"
7/32"
7/32"

1 3/16"
1 3/16"
⁽¹¹⁾
1 3/16"
1 3/16"

.065"
.065"
⁽¹²⁾
.065"
.065"

.250"
.250"
.250"
.250"
.250"

⁽⁷⁾
⁽⁷⁾
⁽⁷⁾
⁽⁷⁾
.....

.300"
.320"
⁽¹³⁾
.220"
.........

4374S
4377S
4378S
4387S
4411S.SA

500
500
500
700⁽⁵⁾
550

.....
.040"
.040"
.030"
.063"

7/32"
7/32"
7/32"
7/32"
7/32"

1 3/16"
1 3/16"
1 3/16"
1 3/16"
1 1/4"

.065"
.065"
.065"
.065"
.....

.250"
.250"
.250"
.250"
9/32"

..........
⁽⁷⁾
⁽⁷⁾
⁽⁷⁾
1 Rich

..........
.240"
.220"
.240"
..........

⁽¹⁾	Auto. Trans, in "D". Air Conditioner ON (except as noted).

⁽²⁾	Synchro-mesh only. 475 RPM for Auto. Trans.

⁽³⁾	Synchro-mesh only. 500 RPM for Auto. Trans. or with Air Conditioning.

⁽⁴⁾	On Auto. Trans, cars, set idle as low as possible in "D" to prevent creep and harsh shifts in service.

⁽⁵⁾	Air Conditioner OFF (when used).

⁽⁶⁾	With solid seat. 1/2" with resilient seat.

⁽⁷⁾	See text for adjustment.

⁽⁸⁾	Chevy II, Chevelle, Chevrolet - Air Cond. OFF.

Oldsmobile 650 RPM for Air Cond. Cars (Air Cond. OFF).

⁽⁹⁾	1/2" with resilient seat, 7/16" with solid seat, 5/16" with spring-loaded needle, 7/32" with flared tip spring-loaded needle. See "Changes, Cautions, Corrections ".

⁽¹⁰⁾	600 RPM (Checker), 500 RPM (All Chevrolet Engines).

⁽¹¹⁾	-1/3/16" (Chevrolet), 2 1/4" (Oldsmobile).

⁽¹²⁾	.065" (Chevrolet).060" (Oldsmobile).

⁽¹³⁾	.240" (Chevrolet).230" (Oldsmobile).

⁽¹⁴⁾	Set at.240" to correct stalling after cold start. See "Changes, Cautions, Corrections" .

⁽¹⁵⁾	Set at.220" to correct stalling after cold start. See "Changes, Cautions, Corrections" .