5.1.11. Features of maintenance of the engine


Fig. 4.34. Sequence of an inhaling of nuts of fastening of a head of cylinders




Case details of the engine — the block and a head of cylinders do not demand service, except for cleaning of dust and dirt and tightening of threaded connections. Eventually laying of a head of cylinders is pressed down therefore weakening of an inhaling of nuts of fastening of a head, a burn-out of laying and break of gases outside therefore in use through each 20 000 km of a run of the car it is necessary to carry out tightening of a head of cylinders is possible. Nuts of hairpins of fastening of a head of cylinders drag on from the middle of a head to end faces (forward and back) (fig. 4.34).
The inhaling and check of the moments of an inhaling should be done on the cold engine. If to execute this operation on the hot engine, then after its cooling the inhaling of nuts will be incomplete owing to a big difference in coefficients of linear expansion of material of a head, the block and hairpins. For a uniform and dense prileganiye of a head to the block the inhaling should be done in two steps: previously — with small effort and it is final — with the set moment of 83 — 90 N · m (8,3 — 9,0 kgfs · м).

Fig. 4.35. Sequence of an inhaling of bolts of fastening of a cover of yokes




It must be kept in mind that the inhaling of nuts causes change of gaps in the gas-distributing mechanism. Therefore after each such operation it is necessary to check the size of gaps between yokes and cores of valves. If necessary thermal gaps should be adjusted. To a head of cylinders the inhaling of bolts of fastening of a cover of yokes should be made for providing a dense and uniform prileganiye of laying of a cover of yokes in the sequence shown in fig. 4.35.
In operating time of the engine, especially worn-out which rings pass a lot of oil on walls of the combustion chamber and the bottoms of pistons the deposit layer is deposited. The deposit worsens a thermolysis through walls in cooling liquid therefore there are local overheats, the phenomena of a detonation and kalilny ignition, engine capacity decreases, and fuel consumption increases.
At emergence of such signs it is necessary to remove a head and to clear the combustion chamber and the bottom of the piston of a deposit. Before cleaning it is necessary to moisten a deposit with kerosene. It prevents dispersion of a deposit and prevents hit of poisonous dust in airways.
The deposit is also formed during the long work on small loadings of the serviceable not worn-out engine. In this case the deposit burns out at the long movement with high speed.
At removal of a head of cylinders it is recommended to grind in valves (see the subsection "Repair of the Engine").
In use through each 20 000 km of a run of the car it is necessary to check and regulate a gap between valves and yokes. It is necessary to do it on the cold engine (+20 °C) at the tightened nuts of fastening of a head of cylinders and nuts of fastening of racks of an axis of yokes. The thermal gap between yokes and valves has to be within 0,35 — 0,45 mm. At the increased gaps there is a knock of valves, and at reduced perhaps leaky prileganiye of the valve to a saddle and a valve burn-out therefore the sizes of gaps stated above should not be reduced even in the presence of some knock which though is unpleasant aurally, but does not cause violations of normal operation of the engine.
Check and adjustment of thermal gaps is recommended to be made in the following sequence:
- to install the piston of the 1st cylinder in compression step VMT. For this purpose it is necessary, turning a bent shaft a special key, to combine the third tag on a damping part of a pulley of a bent shaft with an edge index on a cover of distributive gear wheels. At a compression step both yokes of the 1st cylinder have to shake freely on axes, i.e. both valves are closed. To check the probe a gap between a yoke and the valve. At the wrong gap to turn off a wrench a nut of the adjusting screw and, turning the screw-driver the adjusting screw, to establish a gap on the probe. Supporting by the screw-driver the adjusting screw, to zakontrit it a nut and to check correctness of a gap;
- to turn a bent shaft half way, to adjust gaps for the 2nd cylinder;
- to turn a bent shaft for a half-turn, to adjust gaps for the 4th cylinder;
- to turn a bent shaft for a half-turn, to adjust gaps for the 3rd cylinder.
At operation of the car it is necessary to check daily oil level in a case and tightness of the lubrication system. Through each 10 000 km of a run of the car it is necessary to change oil in the lubrication system and the filtering element of an oil filter, in due time to wash out the lubrication system and to eliminate the shown thinnesses in connections of details.
    Level of oil is checked at the idle engine on tags on an index core. It is recommended to support oil level about the tag "П". Increase in level above the tag "П" is undesirable as krivoshipny heads of rods will plunge into oil and to spray it, causing education in a case of excessive oil fog. It causes a zabryzgivaniye of candles, intensive formation of a deposit on the bottoms of pistons and walls of the combustion chamber, coking up of rings, smoking of the engine and the raised oil consumption.
Lowering of the level of oil is lower than a tag "About" dangerously as at the same time supply of oil in system stops and smelting of bearings is possible. Level of oil should be checked in a few minutes after filling or a stop of the engine. After replacement of oil it is necessary to launch the engine and to allow it to work several minutes. After a while check oil level as it is stated above.
It is necessary to merge oil for replacement only on the hot engine. In this case oil has smaller viscosity and well flows down. When changing oil it is also necessary to merge a sediment from an oil filter, to clear the internal surface of the case and a core and to replace the filtering element. The filtering element before installation needs to be impregnated with pure engine oil. For ensuring density of a prileganiye of a cover of the filter it is recommended to put it together with laying in the same position what it held before removal. It is not necessary to tighten excessively a bolt of fastening of a cover as it can lead to deformation of a cover. Density of a prileganiye of a cover is checked after launch of the engine. To exclude intake of not filtered oil in the engine, rubber sealing rings of the filtering element have to have elasticity and not have deformation.
At transfer of operation of the engine to other brand of oil it is necessary to wash out the lubrication system fresh oil of that brand which will be used for engine lubricant. For this purpose from a case of the heated-up engine it is necessary to merge old oil, to fill in 2 — 4 mm above a tag "About" on the index of level of oil flushing oil, to launch the engine and to work 15 min. on the idling mode with a small frequency of rotation, to kill the engine, to merge oil from a case, to replace the filtering element and to fill in fresh oil.
During operation to make a dolivka of oil only of that brand what is filled in in the engine.
It is necessary for service of system of ventilation of a case:
- to remove the air filter, hoses of ventilation of a case;
- to uncover yokes and the carburetor;
- to wash out kerosene and to blow air a cover of yokes and hoses;

Fig. 4.29. Scheme of K-151, K-151D carburetors: I \the scheme of control of the economizer of compulsory idling (K-151 for ZMZ-D025,-4026); II \the scheme of control of the economizer of compulsory idling (K-151D for ZMZ-4061, 4063); 1 — the fuel valve; 2 — a float; 3 — a stopper; 4 — an air jet of transitional system; 5 — an emulsion jet of transitional system; 6 — the screw of fastening of a spray of an ekonostat of the second camera; 7 — a spray of an ekonostat of the second camera; 8 — an air jet of the main dosing system of the second camera; 9 — an emulsion tube of the main dosing system of the second camera; 10 — the small diffuser of the second camera; 11 — the final ball valve of the accelerating pump; 12 — a spray of the accelerating pump; 13 — the air gate; 14 — the small diffuser of the first camera; 15 — an air jet of the main dosing system of the first camera; 16 — an emulsion tube of the main dosing system of the first camera; 17 — the block of an air jet with an emulsion tube of system of idling; 18 — an emulsion jet of system of idling; 19 — an air jet of system of idling; 20 — the screw of factory adjustment of composition of mix; 21 — the main fuel jet of the first camera; 22 — a cap; 23 — a carburetor cover; 24 — the adjusting screw of restart-up of fuel of system of the accelerating pump; 25 — a displacer; 26 — the carburetor case; 27 — the inlet ball valve of the accelerating pump; 28 — a cover of the accelerating pump; 29 — a spring; 30 — the lever of the drive of the accelerating pump; 31 — a diaphragm of the accelerating pump; 32 — the electromagnetic valve; 33 — an electronic control unit; 34 — the controller; 35 — the microswitch; 36 — perepuskny a jet of the accelerating pump; 37 — a diaphragm of the economizer of compulsory idling; 38 — the valve of the economizer of compulsory idling; 39 — a restrictive cap; 40 — the screw of composition of mix; 41 — the case of the economizer of compulsory idling; 42 — the screw of operational adjustment of idling; 43 — a tube to the vacuum proofreader; 44 — a butterfly valve of the first camera; 45 — a cam of the drive of the lever of the accelerating pump; 46 — a roller of the lever of the accelerating pump; 47 — the case of butterfly valves; 48 — a butterfly valve of the second camera; 49 — a depression supply tube to the electromagnetic valve; 50 — the calibrated opening; 51 — laying; 52 — the main fuel jet of the second camera; 53 — a tube to the valve of system of recirculation of the fulfilled gases; 54 — a tube of a supply of crankcase gases; 55 — a toplivopodvodyashchy tube; 56 — a drain tube; 57 — the fuel filter




- to clean a copper wire with a diameter of 1,5 mm the calibrated opening 50 (see fig. 4.29) in the case of mixing cameras;
- to provide tightness of all connections at assembly.
At operation it is not necessary to allow work at an open maslozalivny mouth: it leads to hit in the engine of the crude air and causes the increased wear of details of the engine.
To check correctness of assembly and normal work of system of ventilation of a case, it is necessary to press on the working engine at the minimum turns of idling the hose bringing crankcase gases to the carburetor. If engine turns sharply fall or the engine becomes deaf, the system works normally.
    Care of the cooling system - consists in daily check of level of cooling liquid in a broad tank. Liquid level on the cold engine has to be not lower than MIN tag.
The tag of MIN is put on a wall of a broad tank. If necessary add cooling liquid in a broad tank. In cases of a frequent dolivka check tightness of the cooling system.
At service of the cooling system it must be kept in mind that cooling liquids "Tosol-A 40M", "Lena", "Termosol" are poisonous and flammable as they contain ethylene glycol in the structure. By analogy with the last liquids possess poisonous and narcotic action and ability to get into an organism through skin.
At hit in an organism through a mouth cooling liquid causes chronic poisoning with damage of vitals of the person (affects vessels, kidneys, nervous system). Therefore when using cooling liquid it is necessary to observe the following precautionary measures:
— not to suck in liquid a mouth at its transfusion;
— in operating time with cooling liquid not to smoke and not to eat food;
— when during the work spraying of cooling liquid is possible, to use goggles;
— open sites of skin on which cooling liquid got need to be washed out water with soap.
Through each 10 000 km of a run it is necessary to regulate a tension of belts of the drive of auxiliary units, and also to check tightness of all connections of the cooling system. At detection of drops or insignificant humidity it is necessary to tighten collars of connections.
At considerable leak of liquid for restoration of level water use is allowed in exceptional cases. However at the same time density of mix will inevitably go down and temperature of its freezing will increase. Therefore as soon as possible it is necessary to replace mix with new cooling liquid. At addition in the water cooling system level in a broad tank has to be higher than MIN tag on 7 — 10 cm.
Before winter operation it is necessary to check liquid density in the cooling system which has to be within 1,078 — 1,085 g/cm3 at 20 °C.
Every three years it is necessary to wash out the cooling system and to fill in new cooling liquid, and also it is recommended to check operation of the thermostat and block of valves of a stopper of a broad tank.
To make replacement of cooling liquid in I follow an order:
— to install the car on the horizontal platform;
— to be convinced that the faucet of a heater is open for what to include ignition, to turn the handle 4 regulators of air temperature, to switch off ignition;
— to remove a stopper of a broad tank;

Fig. 4.16. Scheme of connection of radiators of a heater with a faucet and electric pump: I \the scheme of connection with one heater (for GAZ-2705); II \the scheme of connection with two heaters (for GAZ-2705 of "KOMBI" and buses); 1 — a drain faucet of the cooling system of the engine; 2 — a heater faucet with the electric drive; 3 — the electric pump of system of heating; 4 — a radiator of an additional heater; 5 — a heater radiator; 6 — the taking-away heater radiator hose; 7 — a tee; 8 — a tee stopper; 9 — the thermostat case; 10 — the thermostat; 11 — the sensor of temperature of cooling liquid; 12 — a radiator; 13 — a drain stopper of a radiator; 14 — the fan; 15 — the pump of cooling liquid




— to merge cooling liquid from the engine and a radiator through a faucet 1 (see fig. 4.16) and a stopper 13;
— to disconnect a drain hose of system of heating from the union on the engine (on the right side) and the bringing hose from the lower tube of a radiator of a heater;
- on the Kombi GA3-2705 cars and by buses to remove on a floor in a cabin the protection cover of hoses of a heater and to disconnect hoses from a radiator 4 additional heaters, previously having established under the lower tube of a radiator capacity for liquid;
- after discharge of liquid from system of heating to establish the removed hoses on the places.
To wash out the cooling system for what:
- to wrap a faucet 1 and a stopper of the 13th radiator;
- to fill the engine cooling system with clear water through a jellied mouth of a broad tank to normal level and to wrap a tank stopper;
- to launch the engine, to warm up it on average turns to 80 — 90 °C and to work 3 — 5 min.;
- to stop the engine and to merge water as it is stated above.
To fill the cooling system for what:
- to wrap a faucet on the block of the engine and a radiator stopper. The stopper of a tee 8 (see fig. 4.16) has to be turned out on 2 — 3 turns;
- to slowly fill in liquid in a broad tank. If liquid does not leave a tank, then 1 — 2 time vigorously to press the taking-away radiator hose for removal of the accumulated air;
- at emergence of liquid from under a tee stopper — to wrap a stopper.
After gas station it is necessary to launch the engine and, idling, to warm up it before opening of the main valve of the thermostat. At the same time on GAZ cars - 2705 "Kombi" and by buses it is necessary to turn on the electric pump (see the section "Features of System of Heating and Ventilation of the GAZ Car — 2705 "Kombi" and Buses").
To allow to work to the engine as 3 — 5 min. (cycles) with various frequency of rotation of a bent shaft: 3000 min.-1 — 0,5 min.; 1500 min.-1 — 0,5 min.; the minimum turns of idling — 0,5 min.
To check tightness of the cooling system. After cooling of the engine to check liquid level in a broad tank and if necessary to add to norm.
Check of operation of the thermostat consists in check of temperature of the beginning of opening of the main valve, size and time of its full opening. For this purpose the thermostat is removed from the engine and placed in a tank with cooling liquid not less than 3 l and fixed on an arm so that all thermopower element was washed by streams of the mixed liquid. Intensity of heating of liquid after 55 °C has to be not above 1 °C a minute.
Take temperature at which the valve stroke will make 0,1 mm for temperature of the beginning of opening of the main valve. This temperature has to be (80±2) °C.
At a temperature, on 15 °C exceeding temperature of the beginning of opening of the main valve, the size of full opening of the valve has to be not less than 8,5 mm.
Time of full opening of the main valve is defined from the moment of immersion of a thermopower element in liquid at a temperature about 100 °C. This time has to be no more than 80 pages.
The following deviations of parameters of the thermostat of rather nominal rates are in use allowed:
• temperature began opening of the main valve — on ±3 °C;
• loss of a valve stroke — for 20%.
The simplest check of serviceability of the thermostat can be carried out to the touch directly on the car. After launch of the cold engine at the serviceable thermostat the hose connecting a thermostat branch pipe with right (on the car course) a radiator tank, has to heat up when temperature of cooling liquid reaches 80 — 90 °C. At the same time the arrow of the index of temperature of cooling liquid has to be established on a green zone of a scale of the device.
It is necessary to support the correct tension of belts of the drive of auxiliary units. The deflection of a belt of the drive of the fan has to be in limits of 7 — 9 mm, a deflection of a belt of the drive of the pump of cooling liquid and the generator — within 8 — 10 mm at load of each of them of 40 N (4 kgfs).
To carry out check a dynamometer 7870-8679 as follows:

Fig. 4.36. A dynamometer 7870-8679 for check of a tension of belts of the drive of auxiliary units: 1 — the handle; 2 — a scale; 3 — бурт; 4 — the plug; 5 — a level




- to establish a dynamometer by a level of 5 (fig. 4.36) serially on pulleys of the fan and a tension roller, the pump of cooling liquid and the generator;
- to press a hand the handle 1 to a contact of a burt 3 rods with the plug 4 and to define effort of a tension of a belt on a scale 2;

Fig. 4.19. Belts of the drive of auxiliary units: 1 — the drive of the water pump; 2 — a pulley of a tension roller; 3 — a fan drive pulley; 4 — a pulley of a bent shaft; 5 — a generator drive pulley




- to adjust if necessary a fan drive belt tension change of provision of a tension roller 2 (see fig. 4.19), a belt of the drive of the generator and the pump of cooling liquid — change of position of the generator.
At a weak tension of belts there is their pro-slipping that leads to defective operation of the fan, pump of cooling liquid and the generator, and also to strong heating and stratification of belts. The excessive tension of belts causes bystry wear of the bearing of the fan, pump of cooling liquid, the generator and a tension roller, and also a pulling and destruction of belts.
     Care of a power supply system. An indispensable condition of reliable work of a power supply system is purity of its devices and knots. It is necessary to fill in only pure gasoline in a tank, and also to periodically merge a sediment and water from a tank.
It is necessary to check carefully tightness of connections of fuel-supply lines and other knots of system at good lighting, with a frequency of rotation of a bent shaft corresponding to idling.
Dribble of fuel creates danger of the fire. Thinnesses of connections are eliminated with tightening of nuts, unions and collars.
Care of the drive throttle and air gates consists in replacement of the details which refused in
- to work.

Fig. 4.25. Drive throttle and air gates: 1, 9 — arms; 2 — a bracket of fastening of draft of the air gate; 3 — a rope cover; 4 — a sealant; 5 and 18 — tips with epiploons; 6 — the coupling; 7 — the handle of draft of the air gate of the carburetor; 8 — the lever with the limiter; 10 — the lever with the roller; 11 — a pedal; 12 — a bracket of fastening of a rope; 13 — the sector of the lever of the drive of butterfly valves; 14 — the lever of the drive of the air gate of the carburetor; 15 — draft; 16 — a rope; 17 — adjusting nuts




Installation of the drive of butterfly valves (see fig. 4.25) needs to be carried out as follows:
— to establish tips with epiploons 5 and 18 in a guard of a front of a cabin and an arm of the 7th carburetor;
— to pass a rope through openings of tips 5 and 18 from a cabin;
— to insert the ends of an internal tube of a cover 3 into nests of tips 5 and 18, and to put on the ends of an external tube the ends of tips;
— to put the end of a rope with a tip in a nest of the connecting coupling 6 and to fix it by a finger with the forelock on the pedal lever a cut up;
— holding a pedal 11 pressed to a floor rug, and sector 13 in the provision of completely open butterfly valves, to fix a rope 16 on sector 13 by means of a bracket 12;
— if necessary as much as possible precisely to adjust a rope tension movement of a tip 18 in an arm 1 and by means of nuts 17 (for ensuring full opening and closing of butterfly valves);
- having stopped establishing adjustment, sector 13 in the provision of completely closed butterfly valves (a pedal in the top situation) and to enshrine the lever 8 limiter in the provision of contact with an arm 9.
At installation of flexible draft not to allow abrupt excesses of a rope as in the presence of a bend on a rope its jamming in a cover, and also premature break of a rope and wear of plastic tubes is possible.
     Care of the air filter consists in periodic replacement of the filtering element. For this purpose it is necessary to unfasten five latches and to uncover the filter. At assembly of the filter it is necessary to pay attention to the correct arrangement of the condensing laying between the case of the filter and the filtering element, filter covers, and also connection of the case with the carburetor.
At repair of the filter replace the details which refused work.
    Care of the fuel filter settler consists in periodic discharge of a sediment (through 20 000 km) through a drain stopper, washing of the case of the filter and its filtering element seasonally, once a year.

Fig. 4.27. Fuel filter settler: 1 — a cover bolt; 1 — laying of the filtering element; 3 and 4 — unions; 5 — a washer; 6 — laying of a cover; 7 — a cover; 8 — an arm; 9 — the settler case; 10 — the element filtering; 11 — a spring; 12 — a spring washer; 13 — laying of a drain stopper; 14 — a drain stopper




For removal of the filtering element it is necessary to turn off two bolts of fastening of an arm 8 (see fig. 4.27) a settler to a frame, to turn off bolts 1, to remove the case 9 with an arm 8, to remove a washer 12 and a spring 11.
To wash out the filtering element and the case of the filter pure unleaded gasoline.
At assembly of the filter settler it is necessary to watch correctness of installation of laying 2 and 6.
    Care of the filter of thin purification of fuel consists in periodic cleaning through 20 000 km of a settler of dirt and rainfall, washing of the mesh filtering element or in replacement of the paper filtering element (for release engines till 2001), replacement of the filter in collecting (for release engines since 2001).
    Care of the fuel pump consists in periodic removal of dirt from a head and washing of the mesh filter.
There are two ways of check of pressure developed by the pump.
First way. Check is carried out directly on the car with the engine working at minimum steady turns. The fuel pump is disconnected from the carburetor (power supply of the engine is carried out by drift) and connect to the manometer with a scale up to 100 kPa (1 kgf/cm2). For the serviceable pump pressure has to be within 23 — 32 kPa (0,23 — 0,32 kgfs/cm2). It is possible to check pump pressure, but less precisely, without disconnecting it from the carburetor, and having attached the manometer through the tee screwed at the fuel exit from the pump. Having checked pressure, stop the engine. Indications of pressure on a scale of the manometer have to remain not less than 10 sec. More bystry pressure drop testifies to malfunction of the pump.

Fig. 4.37. The circuitry of the instrument for check of fuel pumps: 1, 4 — three-running cranes; 2 — a tube of a supply of atmospheric air; 3 — a tube of discharge of fuel when pumping the pump; 5 — a fuel supply tube to the manometer; 6 — a fuel supply tube to a flowmeter; 7 — the mercury manometer; 8 — the zero line of the plane of a diaphragm; 9, 13 — drosseliruyushchy cranes; 10 — the fuel pump; 11 — a fuel supply tube from a tank; 12 — the mercury vacuum gage; 14 — an air tube




Second way. Check of the pump is made on the special device (fig. 4.37) which has to provide height of absorption and forcing of 500 mm.
When checking on this device the fuel pump has to meet the following requirements: with a frequency of rotation of a camshaft of the mines-1 device 120 the pump has to provide:
- pressure of zero giving is 23 — 32 kPa (0,23 — 0,32 kgfs/cm2);
- the minimum depression on the line of absorption not less than 48,5 kPa (365 mm of mercury.). Pressure and depression created by the pump have to remain at the switched-off drive not less than 10 sec.;
— giving of the pump with a frequency of rotation of a camshaft of the mines-1 device 1800 has to be not less than 145 l/h.
    Care of the carburetor includes:
— survey and removal of dust and dirt and check of tightness of all connections, traffic jams and caps;
— check and adjustment of level of fuel in the float-operated camera;
— check of adjustment of system of idling;
— cleaning and washing of channels and the dosing carburetor elements.

Fig. 4.38. Adjustment of the float-operated mechanism: 1 — a float; 2 — a uvula for adjustment of a valve stroke; 3 — the valve; 4 — a uvula for adjustment of level of fuel; 5 — a sealing washer




Fuel level in the float-operated camera is checked once a year on the car installed on the horizontal platform, at the idle engine and uncovered the carburetor. Level of fuel has to be in limits of the size "A" (20 — 23 mm from the plane of the socket of the float-operated camera). Adjustment of level is made by a podgibaniye of a uvula of 4 (fig. 4.38) of the lever of a float 1. At the same time the float has to be in horizontal position, and the valve stroke 3 has to be 2,0 — 2,3 mm. The valve stroke is regulated by a uvula podgibaniye 2 levers of the drive. During adjustment of the float-operated mechanism it is necessary to be careful not to damage a sealing washer 5.
If adjustment does not yield desirable result, it is necessary to check the float-operated mechanism of the carburetor. Usually the reasons of the raised or lowered fuel level in the float-operated camera are leakage of a float, its wrong mass or leakage of the fuel valve.
Tightness of a float is checked by immersion it in hot water with a temperature not below 80 °C and hold time not less than half-minute. At violation of tightness of a float what will point an exit of vials of air to, the float should be soldered, previously having removed from it gasoline. After the soldering it is necessary to check its tightness and weight again. The mass of a float assembled with the lever has to be no more than 12,5 g.
In case of leakage of the fuel valve it is necessary to replace a sealing washer 5.
After check and elimination of malfunction of the float-operated mechanism it is necessary to check fuel level size in the float-operated camera again and if necessary to adjust it as it is stated above.
Adjustment of the minimum frequency of rotation of a bent shaft of the engine, content of carbon monoxide (SO) and hydrocarbons (SN) in the fulfilled gases on the mode of idling is made by GOST 17.2.2.03 technique — 87 on special posts in motor transport services or at the service stations of cars (SSC).
The maintenance of CO and CH in the fulfilled gases should not exceed:
3,5% WITH and 1200 million-1 SN with the minimum frequency of rotation of idling (600±50) min.-1;
2,0% WITH and 600 million-1 SN with the increased frequency of rotation of idling (2700±50) min.-1.
Check has to be made on the engine which is warmed up up to the temperature of cooling liquid of 80 — 90 °C and at completely open air gate of the carburetor.
The procedure for test is following:
— to allow the engine to work during 15 sec. at the increased frequency of rotation of a bent shaft;
— to reduce the frequency of rotation of a bent shaft to the minimum turns of idling;
— in 20 sec. at the established minimum frequency of rotation of a bent shaft to make verification of the contents of CO and CH in the fulfilled gases.
Sharp transitions from one mode to another are not allowed.
Before adjustment it is necessary to be convinced of serviceability of system of ignition, having paid special attention to a condition of candles and correctness of gaps between electrodes, and also for ZMZ-4025, ZMZ-4026 and UMZ engines to check and if it is required, to adjust an ignition advancing corner at the minimum frequency of rotation of idling and gaps between yokes and valves of the gas-distributing mechanism.
Adjustment is made on the engine which is warmed up up to the temperature of cooling liquid of 80 — 90 °C.
Adjustment order following:

Fig. 4.39. Adjusting screws of the carburetor: 1 — the removable block of system of idling; 2 — the screw of composition of mix (the quality screw) with a restrictive cap; 3 — the screw of operational adjustment (the quantity screw)




- to remove a restrictive cap from the screw 2 (fig. 4.39) of composition of mix (the quality screw).
- to curtail the screw 2 and the screw 3 of an operational regulilovka of frequency of rotation of idling (the quantity screw) against the stop, but not too hardly, then to unscrew the screw 3 on 5 — 6 turns, and the screw 2 — on 2 — 3 turns.
- to launch the engine and the screw 3 to establish the frequency of rotation of a bent shaft (600±50) of mines-1;
- to adjust the content of carbon monoxide and hydrocarbons in the fulfilled gases, screwing the screw 2 and supporting the specified rotation frequency by the screw 3.
To achieve steady operation of the engine.
For the purpose of providing optimum power setting the plant recommends to establish contents WITH within 0,5 h 1,5% and the maintenance of SN — no more than 800 million-1.
— to increase the frequency of rotation of a bent shaft up to (2700±50) min.-1 and to check the content of carbon monoxide and hydrocarbons. According to GOST 17.2.2.03 — 87 it should not exceed respectively 2% and 600 million-1. Excess of norms indicates malfunction of the carburetor.
- for check of correctness of adjustment to press a pedal of an accelerator and to sharply release it. If the engine decays, then at the expense of an insignificant vyvertyvaniye of the screw 3 to increase the frequency of rotation of a bent shaft, but no more than (600±50) min.-1.
- after the end of adjustment on the screw 2 to put a restrictive cap. Its color has to differ from color of the cap established by manufacturer.
In use screws 2 and 3 independently allowed to make only correction of factory adjustment for receiving the steadiest operation of the engine at the minimum frequency of rotation of idling. At the same time the vvertyvaniye of the screw 2 is allowed only on the corner limited to movement of a tag of a restrictive cap from an emphasis against the stop (approximately on 270 °). Attempts to turn a restrictive cap on a bigger corner will lead to its destruction.
Cleaning and washing of the carburetor have to be made on the pure, specially equipped workbench. For performance of these works the carburetor needs to be disassembled completely then carefully to wash out external and internal surfaces of a cover, the case of the carburetor, diffusers, cases of butterfly valves, to clear of resinous deposits and to wash out fuel, air and emulsion jets, and also channels in the carburetor case. For washing it is necessary to use unleaded gasoline. The carburetor and its details after washing have to be blown by compressed air.
Washing of the carburetor with solvents and rubbing of details with the cleaning ends are not allowed. Cleaning of the calibrated openings is strictly forbidden by metal objects. During the dismantling and assembly it is necessary to use only the serviceable tool in order to avoid failure of shliyets and a smyatiya of nuts.
The inhaling of fasteners of the carburetor should be made evenly, without allowing a buckling of flanges.
    Care of system of recirculation consists in cleaning with a wire with a diameter of 4 mm of openings in an inlet pipe and their purge at the removed recirculation valve through 60 000 km of a run of the car.
    Care of system of production of the fulfilled gases consists in periodic tightening of all fastenings, especially connections of the muffler, resonator and an exhaust pipe. Failed the muffler, the resonator and details of fastening are replaced with new.
    Care of an engine mount consists in periodic (through 20 000 km) check of its state, tightening of fastening of arms and rubber pillows. For increase in durability of pillows it is necessary to watch that on them oil did not get. The failed pillows need to be replaced.