Revision as of 03:11, 27 June 2011

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

1 Jet Locations
2 North American Models
3 Australia Model Specifications
- 3.1 Datsun B310
4 Japan Market Specfications

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

Retrieved from "http://datsun1200.com/modules/mediawiki/index.php?title=Carburetor_Specifications"

Carburetor Specifications