Sensor Plate, Air Flow, Basic Adjustment & Control Plunger
Sensor plate - rest position and free play, checkingRest position, checking
- upper edge of sensor plate must be below edge of air cone a = 1.9 + 0.2 mm (0.074 + 0.008 in)
Rest position, adjusting
- raise sensor plate
- adjust position of sensor plate by bending wire clip (arrow)
CAUTION
- Do not scratch venturi of air flow sensor
- Do not bend leaf spring
Air flow sensor plate free play, checking and adjusting
Requirement
Rest position of sensor plate OK
Note
The free play is the play between control plunger and sensor plate lever (right arrow), measured on the side of the sensor plate that points toward the distributor (left arrow).
- operate starter or remote control US 4480/3 for approx. 10 seconds
- lift up sensor plate slightly until resistance is felt
^ free play specification:
minimum: perceptible play max. to edge of cone = 2.1 mm (0.083 in)
Air flow sensor plate free play, checking and adjusting, continued
If free play NOT OK:
- adjust sensor plate free play on control plunger stop screw
^ specification:
distance a = approx. 0.6 mm (0.024 in) between stop screw and shoulder of hex nut
^ turning in = free play greater
^ turning out = free play smaller
^ 1/4 turn = approx. 1.3 mm (0.05 in) on sensor plate
- after free play adjustment is complete, check idle speed adjustment
- adjust if necessary
Basic adjustment of sensor plate lever
Requirement
Rest position of sensor plate OK
Note
Basic adjustment of sensor plate lever is necessary only if the distributor or air flow sensor is replaced.
- check distance between contact surfaces for fuel distributor on air flow sensor and roller for sensor plate lever
- adjust via mixture adjustment screw, if necessary
^ specification: 19.0 +/- 0.1 mm (0.75 +/- 0.004 in)
Control plunger, removing and installing
- measure and note dimension "a" prior to removing the stop screw
- remove stop screw and detach control plunger
- clean control plunger with gasoline before reinstalling
- check stop screw sealing ring for damage
- replace, if necessary (smaller diameter of sealing ring towards control plunger)
- install stop screw according to previously noted dimension "a"
- check and adjust if necessary rest position and free play of sensor plate - page 22
Note
Mechanical cleaning of control plunger is not permissible. If plunger shows scoring or if cleaning with carburetor cleaner (or equivalent) does not restore freedom of movement, the entire distributor should be replaced.