B210 Carburetor 1978

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B210 used Hitachi DCH306 carburetor for 1978.

Carburetor ID

The ID is inked (not stamped) on this boss on the carburetor:

Carburetor Adjustment

The 1978 carburetors are adjusted exactly the same as the original Datsun 1200 carburetor except for the idle speed RPM number.

After obtain the idle RPM spec, see the main article: Carburetor Adjustment.

North America

5-speeds are exclusive to the FU Engine model, with unique carburetors, jetting and support for maximum fuel economy.

All B210 use A14 engine.

ALL 1978 B210
Carburetor Type: DCH306 (H = Automatic Choke)
Throttle Bores: 26/30 Primary/Secondary
Venturis: 23/27
Float level: 19mm
Float drop h: 1.3-1.5mm
Choke: center mark
Choke resistance: 3.7-8.9 @ 21C (70F)
Ports:
* EGR port
* Vacuum advance port
* Choke pull-off port

California

Manual Transmission: DCH306-11
Auto Transmission: DCH306-15

Main bleeds: 95/80
Slow jets: 45/50

DCH306-11 (M/T)
Main jets: 105/145
Power jet: 40

DCH306-15 (A/T)
Main jets: 104/145
Power jet: 48

Comments: M/T is much richer at full throttle, slightly leaner at cruising.

Canada

4-speed: same as USA
5-speed: same as USA
Automatic: DCH306-12, jetted same as USA Automatic

USA

4-speed: DCH306-60
5-speed: DCH306-37
Automatic: DCH306-14

DCH306-60 (4-speed)
Main jets: 104/145
Air bleeds: 110/80
Power jet: 48
Comments: Jetted Richer than CAL m/t 

DCH306-37 (5-speed)
Main jets: 107/145
Air bleeds: 65/60
Power jet: 48
Comments: Jetted Richer than 4-speed 

DCH306-14/DCH306-12 (Auto transmission)
Main jets: 104/145
Air bleeds: 95/80
Power jet: 40
Comments: Same as CAL auto except leaner full-throttle

Altitude Compensator

CAL models and all models sold in USA high altitude counties.

2 or 3 hose connectors near top of carburetor

For testing at low altitudes, remove the hoses and plug the ports coming out of the casting. The carburetor will run as normal.

See main article: Altitude_Compensator

Vacuum Hoses

Vacuum Advance

Vacuum advance port is always the lowest of any ports on the carburetor.

The Vacuum advance port is just above the mixture screw

Testing: Plug this port and raise RPMs to 1200. If the engine runs at fast idle better than before, the hoses or vaccum advance canister is leaking or connected incorrectly.

You can drive the car with this plugged, but fuel economy and part-throttle power will be down slightly.

EGR Signal Port

EGR

Choke Pull-Off

This long black hose goes to the choke pull-off diaphragm.

Testing: Pull the lower end of this hose off the carburetor, and plug the port. If the engine now idles better, either the hose is leaking or more likely the choke pull-off diaphragm is leaking. The latter is very common with 20-year old+ carburetors.

You can drive the car with this plugged, but after a cold start it will run very rich for some seconds until the choke warms up.