Carburetor Specifications
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.
Overview
DCG - manual choke DCH - electric automatic choke from 1972 USA DCx-306: 26/30 Datsun B110 DCx-286: 26/28 Datsun B10 DCx-340: Datsun 510/620
Also See: Carburetor Repair, Instruction Sheet section
Hitachi DCH306 ID boss
Flange
Hitachi DCG306/DCH306 flange - 61x37mm bolt pattern
Venturis
Venturi (choke) size for B110 is 20 and 26 mm. Smaller than the bore size. The A12 carburetor has small venturis to match the small 1.2 liter engine
choke size MM A12 20 26 A14 22 27 20 27 (China clone) A15 21 27 (AUS B310) 23 27 (USA B310)
20/27 is OK for an A12, but small for an A14
http://datsun1200.com/uploads/photos/30462.jpg
A14 Hitachi flows more air than a Weber 32/36, but is factory jetted for economy. When jetted for power it will out-perform the Weber
CHOKE TOTAL AREA 34/34 23/24 415 cm2 + 452 cm2 = 867 cm2 A12 Hitachi 20/26 314 cm2 + 531 cm2 = 845 cm2 A14 Hitachi 22/27 380 cm2 + 573 cm2 = 953 cm2
V I D E O Hitachi carburetor comparison (click to view)
Jet Locations
jet locations
Main jets are accessible without removing the carburetor
You will need to remove the carburetor top to identify the other jets which are installed. This can be done with the carburetor on the engine.
If the fuel bowl has dirty fuel like this, remove the main jet plugs (bottom of carb) to drain the fuel and rinse with clean gasoline or ether spray or carb cleaner. For more details, see Multiple Symptoms:Drain the fuel bowl.
North American Models
| Year | Engine | Hitachi Model |
| 1971 | A12 | Hitachi DCG306 |
| 72-73 | A12 | Hitachi DCH306 |
| 74 | A13 | Hitachi DCH306 |
| 75-76 | A14 | Hitachi DCH306 |
| 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 |
| 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 |
| Year | Jet Size |
| 1971 | No. 135 |
| 1972-73 | No. 140 |
| 1974 | No. 145 |
| 1975 | No. 150 |
| 1976 | No. 145 |
| 1977-78 | No. 145 |
| Year | Jet Size |
| 71-78 | No. 80 |
| 1977 California 5-speed | No. 60 |
| Year | Jet Size |
| 1971-74 | No. 43 |
| 1975-78 | No. 45 |
| 1978 non-California 5-speed | No. 46 |
| Year | Hitachi Model |
| 71-76 | No. 50 |
1980 FED 106 original 108 countermeasure [non-GFU] CAL 107 original 109 countermeasure
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
B110
16010-H1000 DCG306-1 16010-H1001 DCG306-1A (from '70-Sept.) 16010-H1002 DCG306-1B (from '70-Nov.) 16010-H1003 DCG306-1C (from '71-Jul.) 16010-H1004 DCG306-1D (from '71-Sept.)
Controls * manual choke (DCG) * idle adjust CAP (from '70-Sept.)
Main jet, primary, A12: 98 primary, A12: 97 (from '71-Jul.) secondary, A12: 135 Main air bleed primary, A12: 80 secondary, A12: 80 Slow Jet primary, A12: 43 secondary, A12: 50 Slow air bleed primary, A12: 220 secondary, A12: 100 Power jet (Power Valve) A12: 60
B120
16010-H7802 -7803 16010-G1660 7804-7907 16010-G1615 7908-8109 16010-G2600 8110-8503 16010-G1900 8504-8910 16010-95W00 8910-
B210
16010-H5001 DCG306-2 16010-H5003 DCG306-2A (from '73-8) with anti-diesel valve DCG306-5D with Anti-diesel valve 16010-H7802 A12S.V 7510- 16010-H7860 A14S.V 16010-H8200 A12.S,K
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