DIY carburetor repair Zil 131

In detail: do-it-yourself Zil 131 carburetor repair from a real master for the site my.housecope.com.

With a properly adjusted actuator, it is necessary that the chokes and choke open and close in accordance with the positions of the pedal and manual control buttons.

Incomplete throttle opening leads to a decrease in engine power, and inadequate throttle coverage causes increased engine idle speed and increased fuel consumption.

If the air damper does not open completely, then the combustible mixture is enriched, which causes excessive fuel consumption, and if it is incompletely closed, it becomes difficult to start a cold engine.

First, the foot and manual throttle drives are adjusted, and then the air damper drive.

The foot drive is adjusted by means of a threaded fork on the carburetor rod and the threaded rod of the throttle control pedal in such a way that when the throttle is fully opened, the pedal does not reach the floor by 3-5 mm.

In this case, the throttle pedal travel must be at least 160 mm.

At the end of the adjustment, the rods are secured with locknuts.

The manual drive of the chokes is adjusted with a clamp, which is installed at the end of the drive cable so that when the drive handle is fully retracted, there is a gap of 2.0-3.0 mm between the clamp and the bracket attached to the rod.

This gap is necessary so that when the manual choke handle is retracted, the return spring ensures that the chokes are covered.

The throttles in the closed position must tightly cover the channels of the mixing chamber; a gap of not more than 0.05 mm is allowed between the channel wall and the choke edge.

Video (click to play).

When adjusting the air damper drive, it is necessary to set the manual control knob so that it does not reach the stop of the cab shield by 2.0–3.0 mm. In this position, with the air damper fully open, connect the drive cable to the damper lever and clamp it with a screw, then fix the cable sheath in another clamp.

In the closed position, that is, with the handle fully extended, the air damper must completely close the throat channel for air passage; a gap of not more than 0.15 mm is allowed between the channel wall and the flap edge.

Adjustment of low idle speed of the engine. The idle speed adjustment should ensure stable idling with the lowest fuel consumption. The adjustment is carried out with the engine running, the coolant warmed up to normal temperature (80-95 ° C), with normal valve clearances and between the spark plug electrodes, and with the air damper fully open.

In fig. 1 shows a diagram by which it is possible to trace the operation of the idling system of the K-88A carburetor and the process of adjusting the carburetor. The scheme of the K-88 carburetor is similar.

At low idle speed of the engine, vacuum from the intake manifold is transmitted through hole 43 of the idle system and rectangular hole 42 into channel 44. Under the action of the vacuum, fuel from the carburetor float chamber, passing through the main jet 47, is directed to the idle jet 6. To obtain the required mixture composition, air is mixed with the fuel, entering through the cutout 7. The resulting emulsion enters the mixing chamber through holes 43 and 42. At the exit from the holes, the emulsion is mixed with the main air flow passing into the chamber through the slot formed by the edge of the choke 45 and the wall of the mixing chamber.

When adjusting, it should be borne in mind that the K-88A carburetor is two-chamber and that the qualitative composition of the combustible mixture in each chamber is regulated by its own adjusting screw 41 independently of the other chamber. It should be remembered that when the adjusting screws are screwed in, the mixture becomes leaner, and when they are unscrewed, it is enriched.

In fig. 2 shows a method for adjusting the K-88A carburetor on a ZIL-1Z0 car.

Before starting the engine and starting the adjustment, screw the screws 1 of the high-quality idle speed adjustment to failure, but not too tight, and then unscrew each three turns. After that, start up the engine and carry out a quantitative adjustment, that is, set the stop screw 2 to the smallest opening of the throttles, at which the engine should work quite stably. Then one of the screws 1 should be gradually tightened at each test by 1/4 of a turn until the engine starts to work with obvious interruptions due to a large depletion of the mixture in the cylinders. Then enrich the mixture by unscrewing screw 1 1/2 turn. Do the same with the second adjusting screw 1.

Having adjusted the composition of the mixture, you should try to reduce the idle speed by unscrewing the stop screw 2 of the throttles little by little, and then again try to deplete the composition of the mixture with both screws 1 alternately, as indicated above. Usually, after two attempts, it is possible to find the correct position for all three adjusting screws and thereby complete the qualitative and quantitative adjustment of the low idle speed of the engine.

To check the adjustment, press the throttle pedal and immediately release it. If the engine stops, the idle speed must be increased.

With a properly adjusted carburetor, the engine should run stably at 400-500 rpm of the crankshaft.

The way of adjusting the carburetor on a ZIL-1Z1 car is the same as on a ZIL-130 car.

The control and adjustment of the K-88 and K-88A carburetors can be performed on the simplest installations and using templates that can be made in a motor transport company.

ZIL 130 and 131, cars that can be called legendary without exaggeration. They were produced for almost 50 years and were used in almost all areas of industry and defense. The secret of the success of 130 and 131 is very simple - the cars were as reliable as possible and did not let their owners down. This was achieved thanks to the almost perfect spare parts that were produced by Soviet factories. One of these parts is the 88a carburetor, which was installed on these cars. The device rarely failed, practically did not require repair. However, all this is only on condition that the driver monitored the state of the carburetor and periodically adjusted it.

Today ZILs 130 and 131 are still reliable workhorses. However, given the fact that in the 21st century, the production of these cars was significantly reduced, today most of them, one might say, are pensioners of the Soviet car industry. Old people very often require repair, and the carburetor to 88a, over time, becomes not so reliable and if you do not adjust it in a timely manner, the part may fail and you will have to replace it.

Before tackling or adjusting a spare part, you should study the principle of operation of the carburetors installed on the ZIL 130 and 131. So, this is a two-chamber device with a falling air mixture flow and double cutting of fuel. The carburetor chambers in the amount of two pieces are made in one block and operate in all engine modes in parallel.

The carburetor in ZIL 130 and 131, by the way, is made in such a way that its adjustment is not a problem for the driver. If the device gets a little run down, you can set it up to work without the need to remove and disassemble the device. However, before tackling the carburetor setting, it is necessary to study its design even superficially. In particular, the screws, with the help of which the setting is actually carried out:

The screw for adjusting the quality of the mixture for idling.
Throttle lock screw.
Screw for adjusting the number of revolutions.
Throttle stop screw.
Jet holder.

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The carburetor itself is much more complicated. However, this knowledge is enough for the initial setup. Deeper ones are needed rather for repairing the device, however, we will entrust this to qualified auto mechanics. If you have minimal locksmith skills, idle adjustment as a solution to most problems with ZIL 130 and 131 carburetors will not be a problem for you.

One of the main diseases of the Zilov carburetors is the so-called floating idle. Simply put, due to one or another malfunction in the cylinder block, a poor-quality fuel mixture. In this case, the car will noticeably triple at idle, and the revs will noticeably float. The problem is solved quite simply. You just need to adjust the screws responsible for the composition of the fuel mixture. Let's walk through the whole process step by step.

First of all, you need to completely tighten the screw, which is responsible for the quality of the fuel mixture. After the screw reaches the stop, it must be loosened by 4-5 turns. In this way, you will achieve a fuel mixture that is ideally enriched for the cylinder block.
In the same way, tighten the screw for the amount of the mixture until it stops. The only difference is that it only needs to be loosened by 3 turns.
The engine can now be started. After turning on the ignition, be sure to wait until the car is sufficiently warmed up.
Now take a screwdriver and, using the mixture amount screw, adjust the carburetor so that the engine runs stably at 800 rpm.
Now close the quality screw until the engine starts to sneeze. After that, it should be loosened by about half a turn.

Next, tighten the quality screw until the engine becomes unstable. Then loosen it half a turn.

That's all, actually. By such simple actions, you can ideally adjust the idle speed of your ZIL 130 or 131 cars.

True, this adjustment does not always help to remove all problems with the carburetor. Sometimes the device needs repair or more complex maintenance. In total, there are 4 problems with Zilov carburetors. In principle, they are all easily removable and a professional chauffeur will be able to fix everything without going to a car service.

First of all, we are talking about such problems as:

Here are, perhaps, all the malfunctions that can be eliminated without any problems with your own hands. Everything else, most likely, will require the intervention of qualified auto mechanics, who are able to fine-tune the carburetor installed on the ZIL 130 and 131. By the way, you should not undertake this business on your own - the process is very long and laborious and in the absence of practical knowledge, you can completely ruin the fuel system ZIL 131 and 130, in this case, no adjustment will help.All of the above problems with ZIL 130 and 131 carburetors, you will never be touched if you follow a number of simple rules and take care of the carburetor as required by its design:

The most important rule - at every maintenance of the car, check that all connection plugs and carburetor plugs are tight. Leakage of the fuel mixture from the device can have a very detrimental effect on its further operation.

Also, at each maintenance, be sure to remove sediment from the float chamber and clean and flush the channels and jets of the carburetor at least a couple of times a year.(It is best to flush the device with high-octane gasoline, and if the contamination is too strong, acetone can be used for this purpose).

Be sure to dry the washed parts, then clean them again with a soft cloth.

Of course, a clogged carburetor will not necessarily cause it to malfunction. However, if you do not engage in device maintenance, problems with your ZIL will not keep you waiting.

Rice. Diagram of the ZIL-130 carburetor: 1 - air mouth housing; 2 - needle valve for fuel supply with an elastic shut-off element made of a special rubber film; 3 - mesh filter; 4 - filter plug; 5 - channel for balancing the float chamber; 6 - idle jet; 7 - cavity; 8 - full power jet; 9 - air jet; 10 - small diffuser; 11 - annular slot; 12 - nozzle; 13 - air cavity; 14 - hollow screw; 15 - air damper; 16 - automatic valve; 17 - pusher; 18 and 34 - springs; 19 and 21 - stocks; 20 - bar; 22 - annular groove; 23 - body of the float chamber; 24 cuff; 25 - cuff spring; 26 - stem sleeve; 27 - hole; 28 - intermediate pusher; 29 ball inlet valve; 30 - saddle; 31 - ball valve; 32 - thrust; 33 - mechanically driven economizer valve; 35 - fuel channel; 36 - cork; 37 - lever; 38 - gasket; 39 - channel; 40 - needle discharge valve; 41 - screws for adjusting idle speed; 42 - rectangular hole; 43 - round hole of the idling system; 44 - channel; 45 throttle valve; 46 - housing of mixing chambers; 47 main jet; 48 - float; 49 - float spring

Diameter of mixing chambers in mm: 36.0

air gap in mm: 60.0

The throughput of the metering elements when tested with water under a pressure of 1000 mm at a temperature of 20 ± 1 ° in cm3 / min:

main jet: 315
full power jet: 1150
economizer valve: 215
air jet: 860

Distance from the fuel level in the float chamber to the upper plane of the connector of the float chamber housing in mm: 18-19

Distance between the edge of the throttle valve and the wall of the mixing chamber, corresponding to the moment of opening the economizer valve with a mechanical drive, in mm: 9.0

Idling is regulated by a stop screw 2, which limits the closing of the throttle valves, and by two screws 1, which change the composition of the combustible mixture when the engine is fully warmed up and when the ignition system is perfectly correct. Particular attention should be paid to the serviceability of the candles and the correct gap between their electrodes. It should be borne in mind that the carburetor is two-chamber and the mixture composition in each chamber is adjusted independently of the mixture composition of the other chamber with the corresponding screw. In addition, it must be remembered that when the screws are screwed in, the mixture is depleted, and when they are unscrewed, it is enriched.

Rice. Adjustment of the idle speed of the carburetor: 1 - screws for the adjustment of the idle speed; 2 - stop screw

When starting the adjustment, tighten the screws all the way, but not too tight, and then loosen each one three turns. After that, you should start the engine and set with the stop screw such the smallest opening of the throttle valve at which the engine runs quite stably.Then you need to deplete the mixture using one of the screws 41, tightening this screw at each sample by 1/4 turn until the engine starts to work with obvious interruptions due to excessive depletion of the mixture in the cylinders. Then the mixture should be enriched by unscrewing screw 41 by 1/2 turn. After finishing the adjustment of the mixture composition in one chamber, it is necessary to carry out the same operations with the second screw.

After adjusting the mixture, you should try to reduce the idle speed by unscrewing the throttle valve stop screw little by little, and then try again to lean the mixture using the screws, as indicated above. Usually, after two to three tries, the correct position for all three adjusting screws can be found.

Do not set the engine idling speed to a very low speed. To check the idle speed adjustment, you must press the throttle actuator pedal and immediately release it sharply. If the engine stops working, the idle speed must be increased. A properly adjusted carburetor should ensure stable idling of a good engine.

The maximum engine speed is limited by a pneumatic centrifugal limiter, which consists of two mechanisms:

centrifugal sensor rotating from the engine camshaft
a diaphragm actuator that acts on the throttle valves of the carburetor

The limiter is factory set to the maximum speed.

It is necessary to remove sludge from the carburetor and clean it.

It is necessary to wash the ZIL-130 carburetor in clean gasoline or acetone, followed by blowing with compressed air. The carburetor contains rubber and rubberized parts (diaphragm of the restrictor system, paronite gaskets, etc.), in addition, a fuel supply valve and an economizer valve with an elastic locking element (made of special rubber) can be installed, therefore flushing with acetone or solvents based on it is necessary carry out only after unscrewing these units from the body parts of the carburetor. Valve knocking and valve seat squeezing are not allowed.

When disassembling the carburetor, removing the upper housing, it is necessary to unscrew the hollow screw 14. It must be borne in mind that the discharge needle valve 40 is not fixed and may fall out of the housing.

It is strictly forbidden to use wire or any metal objects to clean the jets, nozzles, channels and openings. Do not blow compressed air through the assembled carburetor through the fuel inlet and balancing tube, as this will damage the float.

During long-term storage of carburetors, measures must be taken to protect them from corrosion, contamination and damage.

1 - oil bath 2 - cable hose 3 - oil deflector 4 - cassette fixation springs 5 - cable 6 - housing sealing gasket 7 - throttling cassette 8 - cable spring 9 - tension lever fixing bracket 10 - lever fixing angle 11 - throttling cassette holder 12 - tension lever for fastening the cable 13 - mesh of the filter element 14 - packing reflector 15 - pipe guide pipe 16 - elastic air intake 17 - spacer spring 18 - oil reflector 19 - air intake pipe 20 - filter element housing cover 21 - air supply pipe to the carburetor 22 - air supply to the compressor 23 - central pipe 24 - foam oil-retaining packing 25 - filter bracket 26 - filter element housing 27 - element mesh holder 28 - oil spray and foaming window 29 - sealing gasket holder 30 - hole for contaminated oil drain 31 - mesh holder cassettes 32 - oil spray and foaming ejector 33 - central hole will reflect spruce 34 - support washer 35 - reflector support ring 36 - bonnet louvers 37 - bonnet air channel 38 - air channel flap 39 -hole plug for installation of a 40-type air filter ZIL-130

Air supply diagrams for the air filter

Basic data. Carburetor of vertical type, two-chamber with mixture supply flow. The main metering system works on the principle of pneumatic fuel braking. Enrichment of the mixture with an economizer and an accelerating pump with a mechanical drive. The amount of emulsion in the idle system is regulated by two screws and an air damper with an automatic valve.

Adjusting the carburetor K-88

With a properly adjusted actuator, it is necessary that the chokes and choke open and close in accordance with the positions of the pedal and manual control buttons.

Incomplete throttle opening leads to a decrease in engine power, and inadequate throttle coverage causes increased engine idle speed and increased fuel consumption.

First, the foot and manual throttle drives are adjusted, and then the air damper drive.

In this case, the throttle pedal travel must be at least 160 mm.

At the end of the adjustment, the rods are secured with locknuts.

This gap is necessary so that when the manual choke handle is retracted, the return spring ensures that the chokes are covered.

The throttles in the closed position must tightly cover the channels of the mixing chamber; a gap of not more than 0.05 mm is allowed between the channel wall and the choke edge.

At low idle speed of the engine, vacuum from the intake manifold is transmitted through hole 43 of the idle system and rectangular hole 42 into channel 44. Under the action of the vacuum, fuel from the carburetor float chamber, passing through the main jet 47, is directed to the idle jet 6. To obtain the required mixture composition, air is mixed with the fuel, entering through the cutout 7. The resulting emulsion enters the mixing chamber through holes 43 and 42.At the exit from the holes, the emulsion is mixed with the main air flow passing into the chamber through the slot formed by the edge of the choke 45 and the wall of the mixing chamber.

In fig. 2 shows a method for adjusting the K-88A carburetor on a ZIL-1Z0 car.

To check the adjustment, press the throttle pedal and immediately release it. If the engine stops, the idle speed must be increased.

With a properly adjusted carburetor, the engine should run stably at 400-500 rpm of the crankshaft.

The way of adjusting the carburetor on a ZIL-1Z1 car is the same as on a ZIL-130 car.

The control and adjustment of the K-88 and K-88A carburetors can be performed on the simplest installations and using templates that can be made in a motor transport company.

Checking the fuel level in the float chamber. The main reasons for the increased or decreased fuel level in the float chamber

the carburetor may be the following: float leakage, incorrect weight (normal weight 18.7-19.8 g), seizure or leakage of the fuel supply valve 2 (Fig. 1).

One of the reasons for the increased or decreased fuel level in the float chamber may also be the incorrect installation of the needle fuel supply valve when assembling it on the carburetor air neck housing. Therefore, before proceeding with the adjustment of the fuel level, it is necessary to make sure that all units and parts of the float mechanism are in good working order.

The tightness of the assembled needle valve for fuel supply is checked on a vacuum unit (Fig. 3, a). The needle valve assembly 4 with the gasket 5 is installed in the body 6, the tube of which is screwed into the tee 7.

The work of the installation is as follows. When the valve 8 is open and the piston 9 moves with the rod 10 in the direction indicated by the arrow, a vacuum is created in the cylinder, under the action of which the needle valve is pressed against its seat, and the water in the glass tube 2 rises. The level of the water column is equal to the vacuum in the cylinder. The piston must be moved until the water in the glass tube reaches a height of 100 cm on the Z scale from the water level in tank 1, then close the tap 8. If the needle valve is tight, the water in the glass tube will not go down , in the absence of tightness, the water will go down.

The permissible value of the fall of the water column in 0.5 min can be no more than 10 mm on the scale 3.

To obtain tightness, lapping of the needle valve to the seat is allowed. If after this the tightness is not obtained, then the needle valve must be replaced with a new one. When installing the needle valve assembly 12 (Fig. 3.6) on the air throat body 11, it is necessary to correctly maintain the distance from the top point of the needle valve sphere to the plane of the throat body. This size is adjusted with shims 14, and it should be equal to 13.5-13.8 mm according to pattern 13.

The fuel level in the carburetor float chamber at a pressure in front of the needle valve in the range of 125-170 mm Hg. Art. should be 18-19 mm from the upper split plane of the float chamber body. There are two ways to check the fuel level

The first way consists in the fact that when the engine is running at low idle speed, unscrew the control plug (Fig. 4, a) and through the control hole located at eye level (Fig. 4, b), observe the fuel level. If the level is correctly adjusted, the fuel will be visible, but it should not flow out of the hole.

Second way check is that it is necessary to unscrew the plug that closes the valve channel of the mechanical economizer, and in its place screw in the adapter 1 (Fig. 5), ending with a glass tube 2 with marked risks on it, indicating the limits of fluctuation of the fuel level in the float chamber. The fuel level in the float chamber must be up to the top or bottom mark, i.e. at a distance of 18-19 mm from the split plane of the float chamber.

To obtain the correct fuel level in the float chamber (with the correct installation of the needle valve), bending of the float bracket is allowed: at a high level, the float must be bent down, at a low level - up.

Checking the throughput of the carburetor metering elements. Caring for carburetor jets includes not only flushing and blowing out their calibrated holes, but also checking their flow capacity. The efficiency of the carburetor, and therefore the engine operation, depends on the normal throughput of the nozzles, which is checked once a year.

The throughput of the nozzles is checked on two types of devices: to check the nozzles for water outflow with an absolute determination of the flow rate and to check the nozzles with a relative measurement of the water flow rate.

Instruments with an absolute definition of the flow rate of the orifices give greater accuracy and stability of the readings compared to instruments with a relative definition. Therefore, it is better to use a device with absolute definition (Fig. 6).

The throughput of the jet is expressed in cubic centimeters of water flowing out through the tested jet in 1 min, at a water column height of 1000 ± 2 mm (counting from the support surface of the jet) at a temperature of 20 ± 1 ° C, which is determined by a thermometer 4.

When checking the throughput, the jets must be installed in the devices so that the liquid flows through them in the same direction as in the carburetor. All nozzles must be free of burrs, dirt and oil, rinsed in clean gasoline and purged with compressed air before checking for flow. When calibrating, the dimensions of the orifices of the nozzles are brought to the required size by gradually expanding them. Embossing or soldering holes to reduce their throughput is not permitted. If the diameter of the calibrated orifice of the jet is larger than the norm, then the jet must be replaced with a new one.

The dispensing elements are checked in the following order. Water from the upper tank 1 (see Fig. 6) through the tap 2 through the tube enters the float chamber 16, in which the float mechanism maintains a constant water level equal to 1000 mm from the supporting surface of the tested nozzle.From the float chamber, water through the tap 15 and the tube 13 enters the housing 12, rises along the glass tube W and simultaneously flows out through the checked nozzle 5 screwed into the holder 11. The water flowing out through the checked nozzle enters the measuring beaker 6 or the tray 7, from where through the tap 9 enters the lower tank 10. From the lower tank, water, as required, can be supplied by compressed air from a compressor or a hand pump to the upper tank 1 through a pipe 14; taps 8 and 9 must be closed at the same time. After filling the upper tank, first open the tap 8, and then the tap 9 to avoid overfilling the tray 7 with water.

To determine the throughput of the nozzle, it is necessary to put a measuring beaker 6 under the flowing stream of water and determine the time of filling it with water using a stopwatch. The flow rate of a nozzle is defined as the quotient of the amount of water in the beaker in cubic centimeters by the time it is filled in minutes. If the flow of water is stopped after exactly 1 minute, then its volume in the beaker will indicate the throughput of the jets in cubic centimeters per minute.

For normal operation of the carburetor, it is also necessary to check the tightness of the valve 34 (see Fig. 1) of the economizer with a mechanical drive; the check can be carried out on a vacuum unit (see Fig. 3, a) in the same way as the fuel supply needle valve is checked. You should also check the fit to their seats of the ball 29 (see Fig. 1) and needle 40 valves of the accelerating pump, as well as their freedom of movement. It is also necessary to check the correct operation of the movable mechanisms of the economizer valve with a mechanical and pneumatic drive, an accelerator pump, an air damper 15 and chokes 45, which are not allowed to hang or jam.

Video (click to play).

When checking the needle valve 40, it is necessary to unscrew the hollow screw 14 and remove the valve, remembering that the valve is not fixed in its seat, and therefore it can spontaneously fall out and get lost.