Hitachi Twin Carb Adjustment

(Difference between revisions)

Revision as of 02:24, 22 August 2009

Idle Mixture

Choke Cable Adjustment

Adjust the fast idle or "starter interlock", so that when the choke is engaged, it forces the throttle plate open slightly.

1. Squeeze the choke lever as shown (nozzle will move down). The yellow connecting link will force the throttle open slightly.
2. Measure the throttle plate opening

   0.6 mm

3. Adjust the amount of opening by bending the link.

Throttle opens by 0.6 mm (measured between edge of plate and throttle bore)

Float Level Verification Check

To check the float level, attach a sight glass to the drain plug.

1. Remove drain plug. Catch gasoline in a cup.
2. Take a 5/16" hose L-fitting. Fit clear 30mm plastic tubing pointing up, and jam the fitting into the drain hole. Make sure it is secure. Position it parallel to the bowl (straight up/down).

   Nissan had a tool for this, number ST19200000 "Float level gauge"

3. Start the engine and let it idle.
4. Measure the level of fuel in the tube
   • 22-24 mm from fuel bowl gasket
   • Adjust float if too high or too low

Float Level Static Adjustment

When replacing the float level needle and seat, set the static level of the float.

1. Remove Float Chamber cover
2. Place it upside down and level
3. Level from top of brass lever to flange (without gasket) should be:

   11-12 mm

4. If needed, adjust lever by carefully (and slightly) bending inner tab of brass lever.

Piston Lift Check