Hitachi DCx carburetors have different specifications depending on market, year, state and other factors. All A-series engines used Hitachi DCx-306 carburetors 26/30 bores, except for the A10 engine which used a smaller DCG-286 model with 26/28 bores. A12 carburetors have 20/26 primary/secondary venturis, and other engines used bigger venturis up to A15s which have bigger 21/27 or 23/27 venturis.
- DCG - manual choke
- DCH - electric automatic choke
Also See: Carburetor Repair, Instruction Sheet section
Hitachi DCH306 ID boss
Hitachi DCH306
Jet Locations
You will need to remove the carburetor top to identify the exact jets which are installed. This can be done with the carburetor on the engine.
To remove the top:
- remove pump lever cotter pin. The hardest part is disconnecting the throttle pump linkage on the outside of the carb. This is the long lever along the top of the carb and rods that connect the throttle to the pump. There are also small clips that hold the levers. Be careful and don't lose them
- remove choke linkage cotter pin
- remove and plug fuel line
- remove choke pull-off hose
- remove the top screws
- if equipped, disconnect auto choke wires and idle cut solenoid wires
North American Models
Carburator Models
Year | Engine | Hitachi Model
|
1971 | A12 | Hitachi DCG306
|
72-73 | A12 | Hitachi DCH306
|
74 | A13 | Hitachi DCH306
|
75-76 | A14 | Hitachi DCH306
|
Primary Main Jet - North American Models
Year | Jet Size
|
1971 | No. 98
|
1972 | No. 97
|
1973 | No. 95
|
1974 | No. 104
|
1975-76 California | No. 104
|
1975-76 | No. 102
|
1977-78 California Manual Trans. | No. 105
|
1977 | No. 104
|
1978 California Manual Trans. | No. 105
|
1978 | No. 104
|
1978 Federal | 5-speed No. 107
|
Main Air Bleed
71-73 No. 80
|
74 No. 65
|
75-77 No. 95
|
1978 All California No. 95
|
1978 Four-speed No. 110
|
1978 Five-speed No. 65
|
1978 Automatic No. 95
|
Secondary Main Jet
Year | Jet Size
|
1971 | No. 135
|
1972-73 | No. 140
|
1974 | No. 145
|
1975 | No. 150
|
1976 | No. 145
|
1977-78 | No. 145
|
Secondary Air Bleed
Year | Jet Size
|
71-78 | No. 80
|
1977 California 5-speed | No. 60
|
Primary Slow Jet
Year | Jet Size
|
1971-74 | No. 43
|
1975-78 | No. 45
|
1978 non-California 5-speed | No. 46
|
Secondary Slow Jet
Year | Hitachi Model
|
71-76 | No. 50
|
Australia Model Specifications
Hitachi DCG-306 (G indicated manual choke)
NOTE: B310 A15 uses DCF-306, which differs from DCG as follows:
* vacuum secondaries, instead of counterweighted secondaries
* replaceable sight glass with O-ring
* modified choke fast idle system
Datsun B310
source: Gregory's
Controls
Idle Cut Off Solenoid (anti-diesel valve)
Servo Diaphragm
Dashpot
Venturi
primary, A12: 20 mm
primary, A14: 22 mm
primary, A15: 21 mm
secondary, A12: 26 mm
secondary, A14/A15: 27 mm
Main jet,
primary, A12: 96
primary, A14: 104
primary, A15: 100
secondary, A12: 150
secondary, A14: 150
secondary, A15: 145
Main air bleed
primary, A12: 80
primary, A14: 65
primary, A15: 70
secondary, A12: 80
secondary, A14: 60
secondary, A15: 80
Slow Jet
primary, A12: 43
primary, A14: 46
primary, A15: 43
secondary, A12: 50
secondary, A14: 50
secondary, A15: 70
Slow air bleed
primary, A12: 220
primary, A14: 170
primary, A15: 100
secondary, A12: 100
secondary, A14: 100
secondary, A15: 100
Power jet
A12: 60
A14: 60
A15: 40
Japan Market Specfications