Engine 168f DIY repair

Like any technique, a walk-behind tractor requires timely maintenance and repair. And it is advisable to entrust their implementation to specialists who have the necessary tools and equipment and know their job well. However, if you are also familiar with the device of internal combustion engines and understand the topic of mechanical engineering, then you can do a lot of what may be required to restore the operability of the machine yourself.

Diesel and gasoline engines have different motor resources. For the former, the normal figure is 4000 m3 / h, but the latter are capable of providing only 1500 m3 / h. Despite this, diesel models of walk-behind tractors are not in high demand. After all, both when buying and during operation, they are much more expensive. Therefore, most likely you are working with a walk-behind tractor equipped with a gasoline (carburetor) engine.

All breakdowns that may arise during the operation of agricultural mini-equipment can be conditionally divided into two categories:

1. Engine malfunctions:

• startup problems;
• malfunctions.

1. Malfunctions of other units and mechanisms:

• improper clutch operation;
• breakdowns in the gearbox;
• problems with the chassis;
• malfunctions of control and automation;
• malfunctions of walk-behind tractor systems (cooling, lubrication, etc.).

In many ways, the success of repairing a suddenly out of order machine depends on the correctness of the diagnostics. With regard to maintenance, it is carried out precisely in order to identify small malfunctions, which subsequently lead to serious ones.

Video (click to play).

If you do not have the necessary knowledge, premises, tools and materials necessary for servicing and repairing the motor, entrust the work to a specialist!

If attempts to start the walk-behind tractor were unsuccessful, this means that there are malfunctions in the engine or starting system. In order to determine the source of the breakdown, you first need to check the spark plugs.

If the spark plugs are dry, this means that the fuel mixture is not entering the engine cylinders. There may be several reasons for this:

• there is no fuel in the tank;
• the fuel supply valve is closed;
• the hole in the gas tank plug is clogged;
• foreign objects have entered the fuel supply system.

To fix problems with the fuel supply, you must:

1. Fill the tank of the walk-behind tractor.
2. Open the fuel cock.
3. Clean the drain hole located in the fuel filler cap.
4. Remove the fuel cock, drain the fuel tank and rinse it with clean gasoline. After that, remove the connecting hose on the side of the carburetor and blow it out together with the carburetor nozzles without disassembling the latter using the fuel pump.

If fuel enters the carburetor but does not reach the cylinder, the problem is with the carburetor itself. To eliminate it, this unit must be removed, disassembled and cleaned. Well, after that - assemble and install in place. Therefore, before performing all the necessary manipulations, it does not hurt at all to refresh the memory of the device and the principle of operation of the carburetor.

In the event that, when checking the candles, they turned out to be wet, i.e. fuel is supplied normally, but the engine does not start, the problem may be as follows:

1. Failure of the ignition system:

• there is a characteristic carbon deposit on the spark plug electrodes (it is necessary to clean the candles with emery, after which they should be rinsed with gasoline and dried);
• the size of the gap between the electrodes does not correspond to that specified by the manufacturer in the engine operating manual (the gap is adjusted by bending the side electrode to the required dimensions);
• insulators for spark plugs or high-voltage wiring are damaged (defective plugs and wiring must be replaced);
• the STOP button is shorted to ground (for normal engine start, the short circuit must be removed);
• contacts in the angles of the candles are broken (contacts should be put in order);
• the gap between the magnetic shoe and the starter does not correspond to the standard value (gap adjustment is required);
• defects are found on the stator of the ignition system (the stator must be replaced).

1. Air leaks through the seals of the carburetor, spark plugs, plug and cylinder heads, as well as the carburetor and engine cylinder connections.

If a leak is detected in the connections, it is necessary to tighten the fastening bolts, tighten the spark plugs and check the integrity of the gaskets between the plug heads and the cylinders.

1. Incomplete closure of the carburetor choke.

To eliminate this problem, it is necessary to ensure free movement of the damper by checking the quality of the drive. If jams are found, they must be eliminated.

Compression and carburetor malfunctions

It so happens that the launch is carried out, but its process is significantly complicated. At the same time, the engine of the walk-behind tractor is extremely unstable and cannot develop power sufficient for normal operation.

The reason for this may be loss of compression, which can be identified by:

• soot on the working surfaces of the valves, as well as the seats of the cylinder blocks;
• deformation of the intake valve;
• wear of the piston rings.

In order to restore compression, you must:

1. Check the technical condition of the engine timing mechanism, clean the parts contaminated with carbon deposits, and if there are any defects, replace them.
2. Check the condition of the piston rings and replace defective components.

If, during engine operation, black smoke comes out of the muffler, and an excess of oil is detected on the spark plug electrodes, or they themselves are covered with carbon deposits, this means that:

• an oversaturated fuel mixture is fed to the carburetor;
• the sealing of the carburetor fuel valve is broken;
• the oil scraper ring of the piston is worn out;
• the air filter is clogged.

To fix this problem, you should:

1. adjust the carburetor;
2. replace the leaky valve;
3. replace worn piston rings;
4. clean or replace a defective air filter.

In the event that, when the engine is running, light smoke comes out of the muffler, and the spark plug electrodes are dry and covered with a white coating, this means that a lean fuel mixture enters the carburetor. This problem is eliminated by adjusting the carburetor operation.

Units and components of motors that are installed on agricultural mini-machinery are exposed to significant loads. They can also fail during the operation of the unit, which will very quickly lead to serious failures.

If suspicious noises, jerks and irregularities in the operation of the walk-behind tractor systems are detected, it is very important to immediately turn off the engine, and then let it cool down - only after that it will be possible to fix the problem.

If, during operation, the motor starts to gain momentum on its own, i.e. is "running out", most likely this means that the fastening of the regulator and traction levers is loose. In this case, the user will have to readjust the motor control drive.

Sometimes, when the throttle is fully open, the engine does not accelerate when the throttle is pressed, but on the contrary begins to lose power until it stops completely. This is a clear sign of overheating, so the walk-behind tractor must be turned off and wait until its components have completely cooled down. After that, you should check the oil level in the crankcase, and also check the cleanliness of the ribbed surfaces of the blocks and cylinder heads.

With increased engine loads, it can jam. There may be several reasons for this:

• not enough oil in the crankcase;
• a nadir formed on the lower head of the connecting rod;
• the connecting rod or oil spray is completely out of order.

If the motor of the walk-behind tractor is jammed, it will have to be disassembled and the condition of the main units and components should be checked: faulty, deformed, melted, etc. subject to replacement.

What to do if the motor block motor works intermittently and does not develop the required power? There may be several reasons for this behavior:

Air does not enter the carburetor, which means that the fuel does not burn well - the filter will have to be cleaned or changed.

Fuel residues and combustion products form a thick deposit on the inner walls of the muffler, which must be removed.

In this case, the assembly will have to be removed, disassembled and properly cleaned all of its components. After that, the carburetor must be assembled and properly adjusted.

1. Wear of the cylinder-piston group.

Temperature and high loads do their job, and even the most durable metal wears out and deforms over time. Such parts should be replaced immediately, otherwise you can pay for this with irreparable damage in the engine itself.

1. Damaged ratchet housing or ratchet

The presence of this problem is indicated by the lack of movement of the crankshaft when the engine is started. To replace the clutch housing and ratchet, you will have to completely disassemble the starting block.

1. Loosen the screws securing the starter housing to the engine housing.

If the starter cord does not return to its original position, the starter motor must be adjusted. To do this, the screws are loosened and the position of the knot is set by hand so as to ensure the normal return of the cord.

A fairly common reason for the lack of a return stroke of the starter cord is the failure of the starter spring - it will have to be replaced.

The service life of any equipment is significantly increased by competent maintenance of its main units and components. The promptness of replacing worn-out spare parts is also of great importance. Therefore, in the event of the slightest malfunctions and malfunctions, they should be addressed immediately - as a result, this will prevent much more serious and expensive problems.

Are you here »Homemade mini tractor and everything to it» Engines »The problem with the engine lifan 168f

• • most likely the speed regulator has lost its spring. she is small and often flies.

    • • I turned it off, when the sensor was turned on, it was completely deaf.

        most likely the speed regulator has lost its spring. she is small and often flies.

        Wow. And where does she stand.

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        Edited by togy (Jun 6, 2011 10:10:15 PM)

        • • I have changed the old engine for a lifan 168f. He worked for a year and started to smoke. At the same time, when I was finishing the work, it was stalling constantly (the oil sensor was triggered), I pulled badly. in one word he was worn out. I changed the rings (380 rubles + 0.5 days of work) began to start from a half-barrel, does not smoke, does not stall (I bought SAE-30 oil 5 liters in a tractor store, a little more expensive than 0.6 liters in a motoblock store). Pleased: adjusting the valves (on the exhaust valve there is a cap like a Muscovite one, on the suction valve there is no such cap), it can be disassembled with keys for 10 and 12. Barely - barely unscrewed the connecting rod bolts, I had to turn the small head for 10 with a gas wrench (the key is small about 200mm long)
            Regarding the adjustment, I found in NET the Russian version of the operating instructions, the spare parts catalog and, in principle, the questions disappeared by themselves.

            Which oil to use after repair?

            

            

            The mirror on the cylinder is normal. I think the oil came from the side of the head. Thanks for the photo, it's always good to see. I pour 10w 40 into my engines with semi-synthetics, the manufacturer recommends sae 30, from these I would choose TNK.

            leg wrote:
            Worn or broken valve stem seals are also relevant

            No, it's not relevant here. there is only one cap, on the intake. Well, once we have sorted it out, you can change it - a penny of business.

            Good day everyone! Finally scattered this Chinese dviglo.I was amazed that this engine does not have any even primitive oil purification system. The cause of my troubles was the oil scraper ring worn out nafig, at first I even thought that it had lagged (you can see it in the photo), but as it turned out not. The piston is slightly worn, the finger in the bosses and in the connecting rod bushing slides easily, but does not dangle, it pleases!

            

            

            Bottom line: wash everything, duplicate the rings (preferably Honda), change oil seals, gaskets, nevertheless, in the future I decided to use XADO 15W40 oil with revitalizant (checked, there is an effect!)

            Hello, tell me why the lifan168f-2 engine does not work steadily and smokes a lot and also shoots into the exhaust pipe

            Hello. tell me there is a washer on the camshaft? 188f

            Hello, friends! Question: after two years of active use of Lifan 168F-2 engines in karting, they had to be repaired several times (crankshafts broke, piston rings had to be changed, etc.). After repairs, I assembled the motors for sealant, i.e. I removed the gasket between the block and the block cover, because in hot weather it was simply punctured. The motors assembled for the sealant worked normally, but after two years the following thing very often began to appear: the cylinder block cover bolts loosened up, turned out and, accordingly, the engine oil was leaking out (leaking out). Maybe after a certain number of repairs, the thread wears out on the blocks? Maybe you should assemble motors with a thread lock or Grover washers?

            desant82 wrote:
            Hello, tell me why the lifan168f-2 engine does not work steadily and smokes a lot and also shoots into the exhaust pipe

            desant82, You need to clean the carburetor, also try to start the engine without the air filter, see how it works

            Grabber wrote:
            Hello. tell me there is a washer on the camshaft? 188f

            Grabber, No washer on the camshaft, only a decompressor

            Tell me what to do.
            Something my "Lifan 168F2", installed on the MB "Salut" in 2013, instead of the standard DM-1, began to be capricious: the engine starts up normally with a closed air damper (as always from the beginning of operation), but as soon as it is opened, it starts to spontaneously change rpm from maximum to minimum, then again. You can see how the throttle control lever on the carburetor spontaneously moves. If you pull the spring with your fingers, it works stably at maximum speed. Let go - again starts to change the speed.
            So far, I have been working somehow, closing the air damper - in a certain position (approximately on average), the revolutions are kept high enough and the engine is running.
            What to do? Maybe the spring has “sat down” during operation and needs to be replaced? But the attack happened suddenly.

            Slava1, Try to disassemble and flush the sump.

            kuzmjch wrote:
            Slava1, Try to disassemble and flush the sump.

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            kuzmjch,
            He unscrewed the plug bolts and drained the gasoline from the sump on the carburetor. Not only did it not help, but the engine began to smoke and shoot into the exhaust pipe, as much as the flame flew from the muffler.

            kuzmjch wrote:
            Slava1, Try to disassemble and flush the sump.

            kuzmjch,
            He unscrewed the plug bolts and drained the gasoline from the sump on the carburetor. Not only did it not help, but the engine began to smoke and shoot into the exhaust pipe, as much as the flame flew from the muffler.

            Slava1, See the float and the igloo. Apparently the gasoline is gone, the float fell. Then he did not go back, gasoline flowed into the engine.

            My thoughts swarm only in my head. Oh, I'll take the swarm to the dacha, but for the weekend.

            Slava1 wrote:
            Something my "Lifan 168F2", installed on the MB "Salut" in 2013, instead of the standard DM-1, began to be capricious: the engine starts up normally with a closed air damper (as always from the beginning of operation), but as soon as it is opened, it starts to spontaneously change rpm from maximum to minimum, then again. You can see how the throttle control lever on the carburetor spontaneously moves.If you pull the spring with your fingers, it works stably at maximum speed. Let go - again starts to change the speed.

            Were you in the cold? Try to warm up the carburetor with a hairdryer, condensation may freeze, but it will definitely be there, remove the air filter, but if you work in winter, you will need to supply warm air to the carburetor.

            Today I removed the carburetor from the engine and washed everything I could with the Khors carburetor cleaner. The work was done in a heated room, so the ice (if any) had to grow. And on the street it was "near zero." However, after installing a flushed carburetor on the engine, it turned out that flushing did not give any results, it still works unstable.
            In the process of flushing, I found on the outer wall of the carburetor an unmuffled hole with a thread inside, which goes directly into the carburetor after the throttle valve.
            In the photo of the carburetor, the hole is indicated by an arrow.
            What is this hole? After all, through it, bypassing the air filter, air is sucked in and, most importantly, when the engine is running, I covered it with a screwdriver and the engine's operation became more stable when the air damper was open.
            Maybe there must be some kind of adjusting screw or plug lost during operation?

            

            The Chinese company Lifan is a large corporation, uniting many industries: from small-capacity motor vehicles to buses. At the same time, it is also a supplier of engines for a large number of small firms that produce agricultural machinery and small motor vehicles.

            According to the general tradition of the Chinese industry, instead of their own developments, copying of any successful model, usually Japanese, is carried out.

            The widespread engine is no exception. families 168F, installed on a large number of motoblocks, cultivators, portable generators and motor pumps: the model for its creation was the Honda GX200 engine.

            Engine for walk-behind tractor Lifan with a capacity of 6.5 hp, the price of which in various stores ranges from 9 to 21 thousand rubles, depending on the modification, has a classic layout: it is a single-cylinder carburetor engine with a lower camshaft and a rod valve drive (OHV scheme).

            

            Lifan engine

            Its cylinder is made in one piece with the engine crankcase, which, despite the theoretical possibility of replacing the cast-iron liner, significantly reduces its maintainability when the CPG is worn out.

            The motor has forced air cooling, the performance of which is sufficient when working in hot climates even under heavy loads.

            Ignition system - transistor, during operation does not require any adjustments.
            The low compression ratio (8.5) of this engine allows it to run on commercial gasoline of the brand AI-92 any quality.

            At the same time, the specific fuel consumption of these engines is 395 g / kW * h - i.e. per hour of operation at a rated power of 4 kW (5.4 hp) at 2500 rpm, with the correct carburetor settings, they will consume 1.1 liters of fuel per hour of operation.

            The 168F engine family currently includes 7 models with various configuration options and connection dimensions, which have in common the following characteristics:

            • Cylinder dimension (bore / stroke): 68 × 54 mm;
            • Working volume: 196 cm³;
            • Maximum output power: 4.8 kW @ 3600 rpm;
            • Rated power: 4 kW at 2500 rpm;
            • Maximum torque: 1.1 N * m at 2500 rpm;
            • Fuel tank volume: 3.6 l;
            • Engine oil volume in crankcase: 0.6 l.

            The cheapest package with connecting shaft size 19 or 20 mm. Manufacturer's price - 9100 rubles.

            

            Lifan 168F-2

            For more information about the operation of the Lifan 168F-2 engine, see the video: