HITACHI DCG, DCH & DCJ 306 2-Barrel Carburetors: Overhaul: Reassembly

To reassemble, reverse disassembly procedure. Check carburetor linkage for smooth operation. Adjust float and linkage as required.

Fig 1: Exploded View of Typical Hitachi 2-Barrel Carburetor (Datsun)

Courtesy of NOT AVAILABLE

Fig 2: Exploded Weir of Typical Hitachi 2-Barrel Carburetor (Subaru)

Courtesy of NOT AVAILABLE

Fig 3: Exploded View of Typical Hitachi 2-Barrel Carburetor (Mazda)

Courtesy of NOT AVAILABLE

1974 CARBURETOR ADJUSTMENT SPECIFICATIONS

Carb. No.

Idle Speed (Engine RPM)

Float Level Setting In. (mm)

Float Drop Setting In. (mm)

Choke Linkage In. (mm)

Secondary Throttle In. (mm

Unloader Setting In. (mm)

Vacuum Break In. (mm)

Hot

Fast

Datsun

DCH 306-6

800

1800

⁽¹⁾ 748 (19.17)

057 (1.46)

.....

.229 (5.87)

.079 (2.02)

.055 (1.41)

DCH 306-7

⁽²⁾ 650

2700

⁽¹⁾.748 (19.17)

.057 (1.46)

.....

.229 (5.87)

.079 (2.02)

.059 (1.51)

Honda

DCG 306-45

800±50

.....

⁽¹⁾.433 (11.10)

.057 (1.46)

.058 (1.49)

.229 (5.87)

.....

DCG 306-46

750±50

.....

⁽¹⁾.433 (11.10)

.060 (1.53)

.058 (1.49)

.229 (5.87)

.....

Subaru

DCG 306-18

850±50

.....

⁽¹⁾.410 (10.51)

.060 (1.53)

.050 (1.28)

.240 (6.15)

.068 (1.74)

.....

DCG 306-19

850±50

.....

⁽¹⁾.410 (10.51)

.060 (1.53)

.050 (1.28)

.240 (6.15)

.068 (1.74)

.....

⁽¹⁾	Clearance is measured between float tang and fuel inlet needle valve.

⁽²⁾

In Drive.

1975 CARBURETOR ADJUSTMENT SPECIFICATIONS

Carb. No.

Idle Speed (Engine RPM)

Float Level Setting In. (mm)

Float Drop Setting In. (mm)

Choke Linkage In. (mm)

Secondary Throttle In. (mm)

Unloader Setting In. (mm)

Vacuum Break In. (mm)

Hot

Fast

Datsun

Man. Trans.

765

2450-2650

.59 (15)

.051-.067 (1.3-1.7)

.....

.23 (5.83)

.079 (2.01)

.054-.058 (1.36-1.48)

Auto. Trans.

670

2700-2900

59 (15)

.051-.067 (1.3-1.7)

.....

.23 (5.83)

.079 (2.01)

.057.061 (1.44-1.56)

Honda

800 ⁽¹⁾

.....

.44 (11)

.051-.067 (1.3-1.7)

.....

.23 (5.83)

.....

.050-.066 (1.28-1.68)

Subaru

850

.....

.41 (10.5)

.051-.067 (1.3-1.7)

.....

.24 (6)

.128 (3.24)

.050-060 (1.28-1.52)

⁽¹⁾	Hondamatic 750 with transmission in 1st gear.

1976 CARBURETOR ADJUSTMENT SPECIFICATIONS

Application

Idle Speed (Engine RPM)

Float Level Setting In. (mm)

Float Drop Setting In. (mm)

Choke Linkage In. (mm)

Secondary Throttle In. (mm)

Unloader Setting In. (mm)

Vacuum Break In. (mm)

Hot

Fast

Datsun

B210

Man. Trans.

765

2450-2650

.59 (15)

.051-.067 (1.3-1.7)

.....

.23 (5.83)

.079 (2.01)

.054.058 (1.36-1.48)

Auto. Trans.

670

2700-2900

.59 (15)

.051-.067 (1.3-1.7)

.....

.23 (5.83)

.079 (2.01)

.057.061 (1.44-1.56)

F10

700

2450-2650

.59 (15)

.051-.067 (1.3-1.7)

.....

.23 (5.83)

.079 (2.01)

.057.061 (1.44-1.56)

Honda

800⁽¹⁾

.....

.44 (11)

.051-.067 (1.3-1.7)

.....

.23 (5.83)

.....

.050-.066 (1.28-1.68)

Mazda

Calif.

700-750

.....

.44 (11)

.051-.067 (1.3-1.7)

.....

.213-.260 (5.4-6.6)

.....

.044.056 (1.15-1.45)

Federal

700-750

.....

.44 (11)

.051-.067 (1.3-1.7)

.....

.213.260 (5.4-6.6)

.....

.063.077 (1.61-1.95)

Subaru

850-950

.....

.41 (10.5)

.051-.067 (1.3-1.7)

.....

.24 (6)

.128 (3.24)

.050.060 (1.28-1.52)

⁽¹⁾	Hot idle on Hondamatic should be 750 RPM with transmission in 1st gear.

1977 CARBURETOR ADJUSTMENT SPECIFICATIONS

Model

Idle Speed (Engine RPM)

Float Level Setting In. (mm)

Float Drop Setting In. (mm)

Choke Linkage In. (mm)

Secondary Throttle In. (mm)

Unloader Setting In. (mm)

Vacuum Break In. (mm)

Hot⁽¹⁾

Fast

Datsun

B210

Man. Trans.

740

1900-2700

.59 (15)

.051-.067 (1.3-1.7)

.....

.23 (5.83)

.079 (2.01)

.054-.058 (1.36-1.48)

Auto. Trans.

665

2400-3200

.59 (15)

.051-.067 (1.3-1.7)

.....

.23 (5.83)

.079 (2.01)

.057-.061 (1.44-1.56)

F10

700

1900-2700

.59 (15)

.051-.067 (1.3-1.7)

.....

.23 (5.83)

.079 (2.01)

.057-.061 (1.44-1.56)

Mazda

Calif.

700-750

3000-4000

.44 (11)

.051-.067 (1.3-1.7)

.....

.063-.077 (1.61-1.95)

Federal

700-750

3000-4000

.44 (11)

.051-.067 (1.3-1.7)

.....

.044-.056 (1.15-1.45)

Mazda GLC

700-750

3000-4000

.44 (11)

.051-.067 (1.3-1.7)

.....

Subaru

800-900 ⁽²⁾

.....

.41 (10.5)

.051-.067 (1.3-1.7)

.....

.24 (6)

.124 (3.14)

.047-.060 (1.18-1.42)

⁽¹⁾	Auto. Trans, in DRIVE

⁽²⁾	Federal & High Altitude.; California is 850-950 in NEUTRAL

1978 CARBURETOR ADJUSTMENT SPECIFICATIONS

Application

Idle Speed (Engine RPM)

Float Level Setting

Float Drop Setting In. (mm)

Choke Linkage In. (mm)

Secondary Throttle In. (mm)

Unloader Setting In. (mm)

Vacuum Break In. (mm)

Hot⁽¹⁾

Fast

Datsun

B210

Man. Trans.

700

1900-2700

.59 (15)

.051-.067 (1.3-1.7)

.....

.23 (5.83)

.093⁽²⁾ (2.36)⁽²⁾

.071-.078⁽³⁾ (1.80-1.98)⁽³⁾

Auto. Trans.

650

2400-3200

.59 (15)

.051-.067 (1.3-1.7)

.....

.23 (5.83)

.093 (2.36)

.071-.078 (1.80-1.98)

F10

700

1900-2700

.59 (15)

.051-.067 (1.3-1.7)

.....

.23 (5.83)

.093 (2.36)

.071-.078 (1.80-1.98)

Mazda G1C

700-750⁽⁴⁾

3000-4000

.44 (11)

.051-.067 (1.3-1.7)

.....

.22.26 (5.4-6.6)

.....

.044-.056⁽⁵⁾ (1.12-1.42)⁽⁵⁾

Subaru

800-900⁽⁶⁾

.....

.41 (10.5)

.051-.067 (1.3-1.7)

.....

.24 (6)

.110⁽⁷⁾ (2.80)⁽⁷⁾

.047⁽⁸⁾ (1.18)⁽⁸⁾

⁽¹⁾	Auto. Trans, in DRIVE.

⁽²⁾	5-Speed Federal Hatchback is.085" (2.17 mm).

⁽³⁾	5-Speed Federal Hatchback is.079-.085" (1.98-2.17 mm).

⁽⁴⁾	Auto. Trans, is 600-650 RPM.

⁽⁵⁾	Federal. California is.063-.077" (1.65-1.95 mm).

⁽⁶⁾	Federal & High Altitude. California is 850-950 RPM in NEUTRAL.

⁽⁷⁾	Federal. California is.098" (2.48 mm); High Altitude is.102" (2.59 mm).

⁽⁸⁾	Federal. California is.060" (1.42 mm).

1979 CARBURETOR ADJUSTMENT SPECIFICATIONS

Application

Idle Speed (Engine RPM)

Float Level Setting In. (mm)

Float Drop In. (mm)

Choke Linkage Setting In. (mm)

Secondary Throttle In. (mm)

Unloader Setting In. (mm)

Vacuum Break In. (mm)

Hot⁽¹⁾

Fast

Datsun

210

Man. Trans.

700

1900-2700

.59 (15)

.051-.067 (1.3-1.7

.....

.23 (5.83)

.0093⁽²⁾ (2.36)

.071-.078⁽³⁾ (1.80-1.98)

Auto. Trans.

650

2400-3200

.59 (15)

.051-.067 (1.3-1.7)

.....

.23 (5.83)

.093 (2.36)

.071-.078 (1.80-1.98)

310

700⁽⁴⁾

1900-2700

.59 (15)

.051-.067 (1.3-1.7)

.....

.23 (5.83)

.093 (2.36)

.071-.078 (1.80-1.98)

Mazda GLC

750-850⁽⁵⁾

.....

.44 (11)

.051-.067 (1.3-1.7)

.....

.24 (6)

.09 (2.28)

.050 (1.27)

Subaru

800-900⁽⁶⁾

.....

.41 (10.5)

.051-.067 (1.3-1.7)

.....

.24 (6)

.110⁽⁷⁾ (2.80)

.047⁽⁸⁾ (1.18)

⁽¹⁾	Auto. Trans, in DRIVE.

⁽²⁾	5-speed Federal Hatchback is.85" (2.17 mm).

⁽³⁾	5-speed Federal Hatchback is.079-.085" (1.98-2.17 mm)

⁽⁴⁾	740 RPM on Federal vehicles.

⁽⁵⁾	Auto. Trans, is 650-750 RPM.

⁽⁶⁾	Federal & High Altitude. Calif., vehicles are 850-950 RPM in NEUTRAL.

⁽⁷⁾	Federal. Calif., vehicle is.098" (2.48 mm); High Altitude is.102" (2.59 mm).

⁽⁸⁾	Federal. Calif., vehicle is.060" (1.42 mm).