6.5. Carburetor

Removal and installation
Disconnect a wire from the negative plug of the rechargeable battery.
Remove the air filter.
Disconnect from the carburetor a cable of an accelerator and a cable of system a cruise control (if it is available).
Disconnect fuel supply hoses from the carburetor.
Disconnect contact sockets from the carburetor.
Disconnect a cable of control of the air gate (in hand-operated models the air gate).
Disconnect vacuum hoses from the carburetor, previously having marked their arrangement.
Turn off nuts and lift the carburetor so that it was possible to disconnect a wire of a heater of the air gate (only in computer-controlled models the air gate), then remove the carburetor from an inlet collector.
The screw-driver remove laying or consolidation from an inlet collector.
Installation is carried out to the sequences, the return to removal, taking into account the following.
Fill the float-operated camera of the carburetor with gasoline that will facilitate launch of the engine and will lower load of the rechargeable battery.
Replace laying on both sides of a pro-rate.

Fig. 6.4. Check of level of fuel in the float-operated camera through an observation port


After installation launch the engine, check lack of leak of fuel and be convinced that fuel level in the float-operated camera precisely coincides with a tag on an observation port (fig. 6.4). If the level of fuel does not correspond to a tag, adjust the carburetor.
Check the frequency of rotation of a bent shaft of the engine idling and contents WITH in the fulfilled gases.

Repair and adjustment of the carburetor

PREVENTION
Complete repair of the carburetor – the difficult operation demanding certain skills. The inexperienced motorist should address to the service center or auto repair shop.
Because of the changes made by the manufacturer to a design, some elements of the repaired knot can differ from established on your carburetor. Nevertheless the motorist having brief experience of repair work with the carburetor is capable to define these distinctions and to execute repair.

Dismantling
Before work learn the cost and existence in sale of spare parts. Acquisition of the new carburetor, than repair of obviously worn-out unit can appear more expedient.
Clear the external surface of the carburetor solvent and dry up it. Install the carburetor on the pure, well lit desktop. Prepare a large number of small capacities and markers.

Fig. 6.5. Carburetor details: 1 – a diaphragm of the pneumatic drive of the device of opening of the air gate with an arm; 2, 3, 27, 28 – screws; 4 – case of the air gate; 5 – an air jet of the main dosing system of primary camera; 6 – an air jet of the main dosing system of the secondary camera; 7 – big and small diffusers of primary camera; 8 – big and small diffusers of the secondary camera; 9 – needle valve; 10 – float; 11 – main fuel jet of primary camera;
12 – power jet; 13 – accelerating pump; 14 – fuel jet of system of idling of primary camera; 15 – backpressure valve of the accelerating pump; 16 – air jet of system of idling of primary camera No. 2; 17 – main fuel jet of the secondary camera; 18 – cap; 19 – fuel jet of system of idling of primary camera; 20 – the electromagnetic valve of impoverishment of fuel-air mix at the movement by a setup and the switch of compulsory idling; 21 – case of butterfly valves; 22 – bolt; 23 – carburetor case; 24 – diaphragm of the pneumatic drive of a butterfly valve of the secondary camera; 25 – fuel cut-off valve idling; 26 – a diaphragm of the pneumatic drive of the starting arrangement with an arm; 29 – lever of the drive of the accelerating pump


Carefully examine drafts of the drive of throttle and air gates and the accelerating pump. Sketch or mark them if they differ from shown in fig. 6.5.
Disconnect the lever of the drive of the accelerating pump from draft of a butterfly valve. Unhook a lever spring.
Disconnect a hose of the pneumatic drive of the starting arrangement from the union on the case of butterfly valves.
Separate a pusher of system of the accelerated idling from the lever of the drive of a shaft of the air gate.
Unscrew eight screws of fastening of the case of the air gate to the carburetor case. Length of screws is various therefore it is necessary to mark their arrangement.
Lift the case of the air gate, taking aside wires. Leave laying on the place. The piston of the accelerating pump can be removed together with the case.
Clear the float-operated camera and remove fuel and air jets.
Get a float axis from the case of the air gate, remove a float and the needle valve, then turn out a saddle of the needle valve.

Fig. 6.6. Details of the accelerating pump: 1 – restrictive spring ring and ball of the backpressure valve of the accelerating pump; 2 – stopper of the control valve; 3 – piston of the accelerating pump assembled; 4 – lock ring; 5 – filter and inlet ball of the valve of the accelerating pump


Turn out the fuel cut-off valve idling, then establish into place a spring and the piston of the accelerating pump (fig. 6.6).
Remove the pneumatic shock-absorber, the electromagnetic valve of impoverishment of fuel-air mix at the movement by a setup and the switch of compulsory idling (if they are provided by a design).

Fig. 6.7. Arrangement of draft (1) of a butterfly valve, pusher (2) diaphragms, cases (3) butterfly valves and diaphragm assembled (4)


If necessary it is possible to remove diaphragms of the drive of a butterfly valve of the secondary camera and the air gate together with arms. The diaphragm of the drive of a butterfly valve of the secondary camera can be sorted only for survey as spare parts to it cannot be found (fig. 6.7).
If it is required to separate the case of butterfly valves from the carburetor case, keep in mind that one of screws of fastening is located from below, near the gate of the secondary camera.
Turn out the screw of quality of mix of idling, having remembered the speed on which it was screwed subsequently to install the screw approximately on the former place.
Cleaning and check
Wash out all details solvent and blow compressed air. In the absence of the compressor it is possible to use compressed air from a cylinder. It is not allowed to clean jets and channels a wire.
It is not allowed to immerse in solvent the valve of a cut-off of idling, a diaphragm of drives and other elements from rubber or plastic as they can harden, inflate or take irregular shape.
Make sure that in all fuel canals, jets and in other calibrated elements there is no dirt and agnails.
Check absence of damage on the top and lower surfaces of the case of the air gate, case of the carburetor and case of butterfly valves. Make sure that on them there are no remains of laying.
Visually check for wear and ovality of an opening under levers of the drive and plastic plugs, replace strongly worn-out details.
Check purity and wear of the needle valve of a float and saddle of a float, replace details with noticeable deep development and scratches.
Check existence of deformations on a float, levers of a float and for axes, you will correct the deformed details by a podgibaniye, if necessary replace them.
Check wear of a rubber cap of the accelerating pump and existence of cracks on it.
Check extent of development of the screw of adjustment of quality of mix of idling (existence of agnails and ring development).
Check wear of a plate of the air gate and extent of deformation of draft. At strong deformation turn in draft.

Fig. 6.8. Diaphragm of the pneumatic drive: 1 – cover and screw; 2 – spring and diaphragm;
3 – lever of the drive of a butterfly valve


Check tightness of a diaphragm of the pneumatic drive of the air gate and if necessary replace it (fig. 6.8).
Check whether the air gate freely turns.

Fig. 6.9. Observation port of the case of the carburetor: 1 – slip, laying, glass and rubber laying; 2 – screw


If necessary turn out screws, remove and clear elements of an observation port of the case of the carburetor (fig. 6.9).
Check serviceability of a winding of the electromagnetic valve, having connected a conclusion to a positive pole of the battery, and the case with "mass" of the car. When passing current via the coil the core of the valve has to be involved in the case. If it does not occur, replace the valve.

Fig. 6.10. Check of a thermal valve of the device of automatic opening of the air gate: A – air input; B – air outlet


Depression level in a diaphragm of the pneumatic drive of the device of automatic opening of the air gate is controlled by a thermal valve which will be screwed in the case of an inlet collector. The valve should not pass air at a temperature below 19 °C and has to  open completely  at  a temperature above 19 °C. Temperature dispersion of operation of ±3 °C. At desire check serviceability of the valve, having turned out it (fig. 6.10).
Assembly
Assembly is carried out to the sequences, the return dismantling, taking into account the following.
Replace all laying.
Wrap the screw of adjustment of quality of mix of idling on the same speed which was determined at its reversing.
In the course of assembly execute all adjustments given below.
Adjustment of provision of a float on the case of the air gate
Before installation of the case of the air gate it is necessary to measure distance between the lower surface of a float and the plane of the case (without laying) and to adjust the provision of a float. For this purpose perform the following operations:

Fig. 6.11. Measurement and adjustment of provision of a float (the case is turned): 1 – float uvula; 2 – limiter; N – a gap


– turn the case the plane up that the float fell under the influence of a body weight, and measure a gap between a float and the plane of the case. Compare the measured value (the size N in fig. 6.11) to the required value and if necessary turn in a float uvula;

Fig. 6.12. Measurement and adjustment of provision of a float (the case in working situation):
L – gap


– turn the case a float down that the float fell under the influence of a body weight, and measure distance between the lower surface of a float and the plane of the case. If the measured value (the size L in fig. 6.12) does not correspond to demanded, adjust it a float limiter podgibaniye.
Adjustment of a gap of the device of opening of the air gate

Fig. 6.13. Use of the vacuum pump for check of a gap of the device of opening of the air gate


Apply depression about 400 mm of mercury. to a vacuum tube of a diaphragm (fig. 6.13).

Fig. 6.14. Arrangement of draft (1) of the device of opening of the air gate


Close the air gate a little push and measure a gap. The nominal gap makes (3,94±0,16) mm. In need of adjustment of a gap turn in draft (fig. 6.14).
Adjustment of a gap of a diaphragm of the starting arrangement

Fig. 6.15. Arrangement of draft (1) of a diaphragm of the starting arrangement


Check is carried out as well as for the device of opening of the air gate, but the size of a gap has to be 1,94+0,25 mm. In need of adjustment of a gap turn in draft (fig. 6.15).
The accelerated idling

Fig. 6.16. An arrangement of draft (1) of the drive of the accelerated idling


Completely close the air gate and measure by a shaft of a drill or round caliber a gap between the gate of primary camera and a wall of the diffuser. The nominal rate is specified in specifications. If necessary adjust a gap a podgibaniye of draft of the drive of the accelerated idling (fig. 6.16).
Adjustment of the lever of the drive of a butterfly valve

Fig. 6.17. Arrangement of the lever (1) of the drive of a butterfly valve


Check opening of a butterfly valve of the secondary camera. It has to open only after turn of a butterfly valve of primary camera on 45 °, at such angle of rotation the gap between a butterfly valve of primary camera and a wall makes (6,7±0,5) mm. At smaller turn of the gate of primary camera the free wheeling of the gate of the secondary camera should not be felt. Besides, be convinced that the gate of the secondary camera freely turns at completely open gate of primary camera. If necessary execute adjustment by a podgibaniye of the lever of the drive of the gate (fig. 6.17).

PREVENTION
As opening of the gate of the secondary camera is calculated on the pneumatic drive, it is necessary to operate it manually.

Adjustment of quantity
and qualities of fuel-air mix idling
Install the carburetor, warm up the engine and adjust the frequency of rotation of a bent shaft of the engine idling and quality of mix. After adjustment install new protective caps on screws.