Carburetors

ADJUSTMENTS

Accelerator Cable

1. Warm the engine up completely and make certain the high idle cam is not engaged.
2. Check the action of the accelerator pedal. There should be little to no free-play between the normal "at rest'' position and the point that engine speed begins to increase. Correct free-play measurement is 0–0.8 in. (0–20mm).
3. If there is excessive free-play, loosen the cable adjusting nuts located on the cable mount on the carburetor. With both nuts loosened, the cable may be adjusted to remove slack. Do not adjust the cable beyond the point of no free-play; the engine idle speed will be changed.

Float and Fuel Level

1. Remove the top of the carburetor and remove the gasket. The carburetor does not need to be removed for this procedure. Follow the directions within the carburetor overhaul procedure later in this section.
2. Hold the carburetor top and float upside down. Use a float gauge or depth gauge to measure the distance from the bottom of the float (now the top, since it's upside down) to the inside of the carburetor top. The correct distance is 0.76–0.84 in. (19–21mm).
3. If the dimension is not correct, the shim below the needle seat must be changed. Use a thicker shim to increase the measurement (or lower the float level) or a thinner shim to decrease the measurement (raise the float level).
4. The shim kit contains 3 shims: 0.3mm, 0.4mm and 0.5mm. The float measurement will change by 3 times the measurement of the shim installed or removed. Shims may be combined as necessary. Some arithmetic after measuring should provide the correct shim thickness on the first try.
5. To replace the shim, remove the float pin and the float. Remove the needle valve.
6. Use a pair of pliers to gently unscrew the seat at its widest point. Take great care not to damage the seat or the surrounding metal.
7. Slip the shim(s) over the narrow portion of the seat and then reinstall the seat. Gently tighten it without damage.
8. Reassemble the needle valve and float.
9. Re-measure the float height and replace the shim(s) if necessary to get the correct height.
10. Reinstall the carburetor top.

    Fig. 1: Sets of shims are available for adjusting float height — feedback carburetor

    Fig. 2: The shims fit under the seat of the needle valve — feedback carburetor

Throttle Opener

1983–87 PICK-UP AND 1983–86 MONTERO

1. Disconnect the vacuum hose running to the throttle opener port.
2. Connect a hand vacuum pump to the nipple of the throttle opener. Install a tachometer to read engine speed. Make certain the idle speed for the engine is set correctly.
3. Run the engine at curb idle (fully warm). Apply 11.8 in. Hg (39.8 kPa) with the hand pump; idle speed should increase to 900–950 rpm. If the idle does not increase, replace the dashpot/throttle opener assembly.
   1. Remove the throttle return spring from the throttle lever.
   2. Disconnect the throttle opener rod from the free lever.
   3. Remove the two attaching screws and remove the throttle opener/dashpot assembly.
   4. Install the new unit, connect the rod and install the spring.
4. Reconnect the vacuum hose to the nipple. Start the engine, run it at curb idle and turn the air conditioning on. Idle speed should increase to 900–950 rpm.
5. If the throttle opener needs adjustment, do so by turning the screw on the throttle opener/dashpot assembly. Don't turn any other screws to adjust the throttle opener; the curb idle or other important settings may be affected.

   Fig. 3: The location of the throttle opener adjusting screw. Do not adjust SAS 1 or 3 — 1983–87 Pick-ups and 1983–86 Monteros

   Fig. 4: Adjusting the throttle opener — 1983–87 Pick-ups and 1983–86 Monteros

   Fig. 5: The location of the throttle opener setting screw — 1983–87 Pick-ups and 1983–86 Monteros

1988–89 PICK-UP AND 1987–90 MONTERO

1. Identify the vacuum control solenoid on the firewall. Label and carefully remove the two vacuum hoses running to the unit.
2. Disconnect the electrical connector from the solenoid.
3. Connect a hand vacuum pump to the solenoid port which held the vacuum hose with the white stripe.
4. Using jumper wires, connect battery voltage to one terminal of the solenoid and connect the other terminal to a good ground.
5. With battery voltage applied to the solenoid, draw vacuum with the hand pump. Use the chart to check the properties of the valve with proper combinations of vacuum and electricity applied or removed.
6. Remove the 12 volt jumpers. Use an ohmmeter to measure the resistance of the solenoid. Resistance should be 40–46 ohms at 68°F (20°C).
7. If the solenoid does not behave correctly under ALL test conditions, it must be replaced.