Setting the fuel level in the float chamber
The fuel level necessary for the normal operation of the carburetor is ensured by the correct installation of serviceable elements of the locking device.
Correct installation of float 1 (pic. 9-13) check with gauge 4, for which you install it perpendicular to cover 2, which you hold horizontally with the floats up. There must be a gap of no more than 1 mm between the gauge along the contour and the floats.
Pic. 9-13. Setting the fuel level in the carburetor float chamber 21073-1107010: 1 - float; 2 - carburetor cover; 3 - sealing gasket; 4 - gauge for checking the position of the floats; 5 - needle valve
Adjust if necessary by bending the tongue and float arms. The bearing surface of the tongue must be perpendicular to the axis of the needle valve 5 and must not have dents or nicks.
Trigger Adjustment
When turning lever 4 (see fig. 9-10) control of the air damper 5 fully counterclockwise, the air damper must be fully closed under the action of the spring 7. If the damper is not closed, eliminate the cause of jamming.
With the air damper fully closed, press manually on the rod 3 of the starting device until it stops. In this case, the air damper 5 should open by 3.0 mm (starting clearance B). If necessary, adjust the gap with screw 2.
Throttle valve 12 of the first chamber with a fully closed air damper should be ajar by 1.1 mm (starting gap C) If necessary, adjust this gap with screw 10.
Engine idle adjustment
Adjustment is provided by adjusting screw 2 (pic. 9-14) quality (composition) mixture and adjusting screw 1 of the mixture quantity. The adjusting screw 2 is closed with a plug 4. To access the screw, remove the plug with a corkscrew.
Pic. 9-14. Carburetor idle adjustment screws 21073-1107010: 1 - adjusting screw for the amount of the mixture; 2 - quality adjusting screw (composition) mixtures; 3 - sealing ring; 4 - plug of the adjusting screw.
Idle speed adjustment must be carried out on a warm engine (coolant temperature 90-95°С), with adjusted gaps in the gas distribution mechanism, with the correct ignition timing and with the choke valve fully open.
Using the adjusting screw 1 of the amount of the mixture, set the engine crankshaft speed within 750-800 min using the tachometer of the stand-1.
Adjusting screw 2 quality (composition) mix to achieve carbon monoxide content (SO) in exhaust gases no more than 3% at a given position of the screw 1 (CO content is reduced to 20°C and 101.3 kPa (760 mmHg Art.).
Screw 1 restore the crankshaft speed to 750-800 min-1.
If necessary, use the adjusting screw 2 to restore the CO content to no more than 3%.
At the end of the adjustment, sharply press the throttle pedal and release it, the engine should increase the crankshaft speed without interruption, and when it decreases, it should not stall. In case of engine stop, use screw 1 to increase the crankshaft speed within 750-800 min-1.
Install a new plastic plug 4 into the hole for adjusting screw 2 of the mixture quality.
Checking the operation of the second camera blocking mechanism
Turn the air damper control lever counterclockwise from the heater until the damper is completely closed. Then turn lever 19 (see fig. 9-12) throttle control until the damper 23 of the first chamber is fully opened, while the throttle damper 24 of the second chamber must remain in the closed position.
Turn the throttle control lever clockwise to failure, and the throttle control lever 19 until the dampers are fully open. If the second chamber throttle does not open, repair the problem. The reason may be jamming of the lever 20 of the lock of the second chamber or disconnection of the spring 21 of the lock lever.