Needle Valve Leak Test
It is produced on a stand that provides fuel supply to the carburetor under a pressure of 3 m of water. Art. After setting the fuel level in the test tube of the stand, its fall is not allowed for 10-15 s. A decrease in the level of fuel in the test tube indicates a leak through the needle valve. Repair the leak by replacing the needle valve.
Setting the fuel level in the float chamber
The required fuel level is ensured by the correct installation of serviceable elements of the locking device (pic. 54). The distance between the float and the gasket 10 adjacent to the carburetor cover (size A), should be 6.5±0.25 mm. Adjust this dimension by bending tab 8. In this case, the supporting surface of the tab should be perpendicular to the axis of the needle valve and should not have nicks or dents. Check with caliber 67.8151.9505. Hold the cover vertically so that the tongue 8 of the float lightly touches the ball 5 of the needle valve 4 without sinking it. Adjust the value of 8±0.25 mm of the maximum stroke of the float by bending the stop 3. The pulling fork 6 of the needle should not interfere with the free movement of the float.
Pic. 54. Setting the fuel level in the float chamber:
1 - carburetor cover; 2 - needle valve seat; 3 - emphasis; 4 - needle valve; 5 - ball of the locking needle; 6 - pull-back or valve needles; 7 - float bracket; in - tongue; 9 - float; 10 - gasket.
Check float setting when replacing float or needle valve.
Adjustment of the pneumatic actuator of the throttle valve of the second chamber
Before connecting stem 5 (see fig. 43) to lever 7 on the axis of the throttle valve of the second chamber:
- turn the throttle valve of the second chamber to a vertical position;
- press the rod 5 of the pneumatic actuator to the stop and, holding the sleeve 2 from turning, unscrewing or wrapping the rod, adjust its length so that the hole in the tip of the rod 5 is against the pin on the lever 7;
- put the rod 5 on the pin of the lever 7 and secure it with a lock washer;
- fasten the stem 5 with a lock nut, holding the sleeve 2 from turning with another key.
Adjusting the position of the microswitch
Adjustable when the air damper is open. Microswitch 3 (pic. 55) should turn off when lever 2 is turned clockwise until it stops. When lever 2 is turned counterclockwise from its initial position until it stops against the barb A of lever 1, the microswitch should turn on. To adjust the moment of turning on and off the microswitch, loosen the screws of its fastening and turn the microswitch relative to the upper screw to the required position. After completing the adjustment, tighten the fixing screws.
Trigger Adjustment
When turning lever 1 (pic. 56) counterclockwise until it stops, air damper 2 must be completely closed. Moreover, in this position of the lever, the end of the rod 3 must be at the end of the groove of the rod 4 of the starting device, but do not move the rod. Adjust by bending the rod 3.
When the air damper is completely closed, the throttle valve 6 of the first chamber should be ajar by 0.7-0.8 mm (gap C - the distance between the damper and the chamber wall at the location of the vias of the idle system). Adjust this gap by bending the rod 7.
A fully closed air damper should open 5+0,5 mm (clearance B) the rod of the starting device when moving it manually to the right until it stops. Adjust this value with screw 5.
Throttle valve adjustment
Partial opening of the throttle valve of the first chamber, in which the upper antennae of the lever 3 (pic. 57) is in contact with lever 2, should be 6±0.25 mm. Adjust by bending the upper antennae of the lever 3.
Pic. 57. Throttle valve adjustment: a - partial opening of the throttle valve of the first chamber; b - full opening of the throttle valves;
1 - lever on the axis of the throttle valve of the second chamber; 2 - a lever that limits the opening of the throttle valve of the second chamber; 3 - lever rigidly connected to the axis of the throttle valve of the first chamber; 4 - damper drive lever; 5 - throttle valve of the first chamber; 6 - throttle valve of the second chamber.
The full opening of the throttle valves is checked by turning the levers of their drive to the position against the stop. Maximum throttle opening of the first chamber (13±0.1 mm) adjust by bending the lower antennae of lever 3; the second chamber — 15±0.1 mm (for carburetors 2107-1107010 should be 17±0.1 mm).