What’s the best oil for a 4-stroke lawnmower?

Best lawnmower oils for 2021

A lawn mower is a very useful piece of equipment for mowing grass when there is a constant need to care for park areas or lawns. Thanks to it, in the shortest possible time to give a smoothed look to the vegetation, which is rather difficult to do with a manual lawn mower. For the petrol and lawnmower to last longer and not require constant repairs, it must be properly maintained. One of the permanent procedures for this purpose is oil change. Depending on the design of the motor, lawn mower can run on pure fuel or use an oil mixture. Choosing the right oil and fuel for the lawn mower is of utmost importance, as these materials have a direct effect on the life of the engine.

Gasoline lawnmowers can have four-stroke or two-stroke motors (ICE). The rotation/motion of the cutting elements is provided by the energy supplied to them by the engine. The energy is generated by the expansion of the gases created when the gasoline or fuel mixture detonates in the combustion chamber. The very compression of the created gases is provided by the movement of the piston. In general, the simple principle of an internal combustion engine.

In order for such a system to function properly as a whole, there must not be too great a gap between its mating parts. If the gap dimensions are increased due to wear of the working nodes, it will lead to deterioration of the whole engine operation, and over time to the simple inability to start it. The problem will be related to the fact that the system will not be able to achieve the required pressure for combustion of the fuel mixture mixed with atmospheric air.

Engine oil is intended to cover the engine nodes with a thin film in order to slow down their wear process, and also to prevent the formation of burrs on the metal surfaces of the mating parts. This is the primary function of oil in the operation of the gasoline lawnmower engine. However, you should understand that oil does not stop completely the destruction of working units, caused by their friction between each other, but only significantly slows down this process.

In addition to lowering the friction coefficient between the mating working parts of the engine, the oil helps:

  • Providing better cooling of the drive unit during operation, while increasing the level of heat exchange processes between the atmospheric air and the metal;
  • Performing the work of the motor during its operation at the maximum level of intensity, which increases the efficiency of activity and reduces the time costs;
  • Protects the drive unit’s metal from corrosion if the machine is not used for a long time during the cold season.

Thus, engine oil is a special material, capable of ensuring trouble-free operation of the engine, as well as other systems in the mower. If the quality of this material is neglected, the machine becomes more prone to various breakdowns.

Constructional features of four-stroke and two-stroke engines

These engines have much in common in their operating principle. The only difference is that a two-stroke motor has two strokes, and a four-stroke motor has four strokes. One stroke refers to a single downward or upward movement of the piston. Two strokes per revolution of the crankshaft. Under the working stroke of the piston we understand its movement, during which the energy of the gases is converted into useful engine work (its rotation), as a result of combustion of fuel.

In terms of performance and design characteristics, two-stroke and four-stroke engine models differ from each other according to the following criteria:

  • Two-stroke engines have about 1.5 to 1.8 times the power density per liter.
  • They differ in the way they are lubricated.
  • Four-stroke engines are characterized by improved fuel economy (fuel consumption is reduced by 20-30%) and exhaust emissions contain fewer toxic substances.
  • Different methods of feeding fuel mixed with air into the cylinder and venting the exhaust gases. Four-stroke engines have a timing mechanism that opens/closes special valves at the right time, while two-stroke models do not have it. the “exhaust” just goes through stationary holes.
  • Four-stroke models are quieter.
  • The overall design is simpler on two-stroke models.
  • Improved lubrication system in four-stroke models significantly extends their service life. Also, this period is increased due to the fact that the crankshaft rotates at lower frequencies.
  • Two-stroke engines rev up faster and accelerate more easily.
  • Periodic maintenance frequency will be easier for two-stroke models and may well be done yourself.
  • Four-stroke motors weigh more and cost more.

IMPORTANT! It is the absence of a valve timing mechanism that makes two-stroke engines simpler and lighter from a structural point of view. The filling of the cylinder with the air-fuel mixture, as well as its purging from the gas, is carried out by compression/expansion of the mixture and its release/intake through special holes.

Lubrication methods for different types of motors

The use of oil in different types of engines for lubricating internal parts is an essential point in the maintenance process and consists in the fact that two-stroke models are not filled with pure gasoline, but with its mixture with engine oil in appropriate proportions. This mixture, when combined with air, wraps around in the piston assembly, thus lubricating the cylinder walls, together with the connecting rod and crankshaft bearings, as well as the pistons themselves. During the ignition of the fuel mixture, the oil in its composition in tiny droplets also ignites. Products of combustion are converted into exhaust gas and expelled to the outside through open holes.

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IMPORTANT! There are two-stroke engines that supply elements of the fuel mixture (oil and gasoline) separately, but such ICEs are not installed on lawnmowers.

Hammerflex 501-018 SAE 5W-30

Winter semisynthetic motor oil, designed for use in four-stroke gasoline engines of snow blowers, generators, power tillers, mini tractors and other garden and construction equipment and even for lawn mowers. Provides perfect lubrication during cold start, excellent protection against deposits and corrosion, prevents premature wear of the piston group, keeps the engine clean and extends its life.

Replacement recommendations

It is important not only to choose high-quality oil, which by its characteristics will be suitable for your equipment. You also need to know how to pour it into the lawnmower correctly. The rules are uncomplicated, but mandatory to follow:

  • turn the machine on and let the engine idle for a quarter of an hour;
  • remove the cap from the tank and put a container of the required volume for the collection of spent liquid;
  • tilt mower and drain away used material;
  • screw in the plug, place the machine on as level a surface as possible. After that you can open the hole on top;
  • pour the new working fluid, following the recommendations of the manufacturer of the equipment regarding the volume, it is convenient to check the fluid level with a dipstick;
  • Once the quantity of liquid has reached the right volume, you can close the cap.

In most cases, you need to use about 500 ml of fresh oil to replace the used fluid. This norm corresponds to most of the units that are widespread in Russia. There are, of course, exceptions, so it is necessary to study the instructions before replacing the used fluid.

Lawn mower oil requirements

Engines in small agricultural machinery are different from automotive engines, so the lubricant should be different too. Filling the mower with a mixture designed for machines or motorcycles is not allowed: it can cause damage. Even without malfunctions the lawnmower is likely to start working worse: a fluid that is not designed for this type of machine will not be able to cope well with its functions. Therefore, it is recommended to use special oils designed for garden equipment.

General recommendations for lawnmower oil selection

Based on the above engine design features, it is best to use a special lawnmower oil for the lubrication, and it must match the temperature conditions in which the unit will be used. Specialised SAE 30 class grease is regarded as optimum. It is used at temperatures above 5 degrees.

If special is not available, automotive grade greases can be used:

These greases, too, are designed mostly for positive ambient temperatures and a maximum above 35 degrees.

By type of lubricant. mineral and semi-synthetic are acceptable. Fully synthetic would be too expensive. API performance quality level. “SF”, “SG”, “SH”, “SJ” and higher. For four-stroke garden machinery engines, the label should be marked “4T”.

How to fix a lawn mower blade?

A person can buy replacement blades right after purchasing the device, or he can sharpen the existing knife. In any case, once the part has blunted, it must be removed.

First, you should disconnect the electrical device from the power supply and put it on its side. With a petrol mower, things are a bit more complicated.

  • The grass collection tank should be removed;
  • Carefully drain the oil and gasoline into different containers;
  • Disconnect the spark plugs;
  • Stand the mower on its side.

The following steps are directly related to replacing the blade.

  • It is necessary to fix the blade with a log or a board, so as not to cut yourself in the process;
  • Often the blades are mounted on two bolts or one, but a large one, placed in the center. A box spanner or ring spanner is a great helper;
  • Unscrew the bolts counterclockwise, since the right-hand thread is standard;
  • If the factory tightening is stuck and holds very firmly, you can use a special liquid wrench WD-40.

There are also times when the blade adapters, which connect the cutting element to the motor, need to be replaced. Here it is important to understand that each manufacturer supplements products with certain features, so, for example, the specified part from the AL-KO mower cannot be used for MTD.

Using the advice given in the video below, each owner of “garden helper” can learn the methods that allow you to create an adapter with your own hands using basic parts and tools.

What gasoline to fill up

Gasoline for the lawnmower. the second element of the fuel mixture. Its brand is chosen taking into account the manufacturer’s recommendations, described in the passport to the unit. The higher the octane rating, the longer the fuel burns. So, at gas stations you can buy such brands of petroleum products:

AI-92 is more prone to detonation.

Using fuel with a higher octane rating than declared in the manual, the engine is damaged in units with 2-stroke engines, and the piston group is damaged in units with a lower rating.

The mixture is prepared before operation in the proportion that is specified on the cap of the gasoline tank:

This means that 20 ml of oil fluid is needed per 1 litre of fuel.

Manufacturers of petrol mowers with two-stroke engines (e.g. Patriot PT 555 or Champion T336) specify the correct proportion of the fuel mixture in the instruction manual. The proposed mix ratio for the former is 32:1, the ratio for the latter is 50:1.

Lawn mower with a 4-stroke engine does not require pre-preparation of petroleum product. There are 2 tanks in the device of the equipment. Gasoline must be poured into the tank, and the oil liquid must be poured into the drain hole on the crankcase.

Requirements for lawnmower oil

The engines in small agricultural machinery are different from those in cars, so the lubricating fluid must be different, too. Pouring a mixture designed for cars or motorcycles into the mower is not allowed: it can lead to damage. Even if there are no malfunctions, the lawnmower is likely to start working worse: the fluid not designed for this type of equipment will not be able to cope well with its functions. Therefore, it is recommended to use special oils designed for garden equipment.

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Lawn mower oil selection

For trimmer engines choose air-cooled 2T oils for engines with displacement of 50 to 200 cm3. In the first place when buying oil, you should pay attention not to the price, but the protective properties of the material, because a small savings can later become a real headache for the owner and, as a rule, a big expense.

Two-Stroke Lawnmower Oil

The main factor determining the quality of grass trimmer oil is the alkali number. It is this component that eliminates oxidation of rubbing parts and slows down their destruction. During operation the oil gradually loses its alkalinity and becomes oxidized. The optimum level of acidity (Ph) should not be less than 8-9 units.

The viscosity of the oil for brushcutter also has a great influence on the process of operation of the gasoline tool. This determines whether the weed trimmer can be operated at different temperatures. For example, summer brands of lubricants become thick even at low temperatures. Since you only use your lawnmower in the spring and autumn, summer grade oil is the right choice.

Grass trimmer oil needs to have a flash point above 225° C to burn out quickly and cause the piston assembly to wear down hard.

What to look for when selecting oil?

Modern two-stroke brushcutter engines are filled with a mix of AI-92 gasoline and 2T oil. Using fuel with a higher octane rating will cause a higher flash point and consequently a burnout of the lubricant.

Types of STIHL oils

Undoubtedly, the best oil for grass trimmer is the one recommended by the manufacturer, but the owner does not always have the opportunity to buy exactly “branded” lubricant. The experts recommend Shell Helix Ultra, based on Pureplus technology that improves the basic properties of the lubricant.

STIHL HP Ultra, STIHL HP, STIHL HP S oils should be used for gasoline trimmers from the German manufacturer STIHL. Budgetary substitute could be products of the Vityaz company, which by its properties is most similar to the recommended material.

Differences in operation of 2 and 4 stroke engines

There are two ways to lubricate the piston and crank mechanism on two-stroke engines:

In the photo: feeding of oil through the feeder plunger pump into the combustion chamber inlet.

For the second scheme, the future, while in the garden equipment used the first method. the composition of the combustible mixture. The new engines are quiet, economical, but more complicated.

You can use the table and dispenser to prepare a combustible mixture.

A four-stroke engine has a reservoir under the oil, which is used to create protection for the rubbing parts. In this case, the lubrication system consists of a pump, oil filter and tubes, which feed the compound to the nodes. The sump or reservoir method of lubrication may be used. In the first case, the oil is fed into the system from the crankcase and from there it is pumped into the feed tubes. With a “dry sump” the oil droplets collected in the sump are sent back to the tank.

Pictured: Wet Sump Lubricant and Dry Sump Lubricant.

The difference in oil composition for different types of engines is a matter of principle. The oil for a 4-stroke engine must retain a constant composition over a long period of time. Composition for two-stroke engines should have less mineral oil inclusions during combustion to avoid soot formation.

If you have the recommended oil, do not experiment with the selection of a different composition. If not, you choose the oil recommended for 2 or 4-stroke models. Use gasoline above the recommended brand. prematurely go to the replacement of burnt valves, other components.

An important characteristic when choosing a protective ingredient is its operating temperature. The additive must be resistant to heat, but not thicken at low temperatures. That is why each machine has its own oil grade depending on the operating conditions.

Manufacturers

When selecting an oil, special attention must be paid to the oil manufacturer. It is better to choose the brand recommended by the manufacturer of the lawnmower. In the instruction to the technique, you can find information about the oil filled, the frequency of its replacement and recommendations regarding the choice of working fluid.

Also, many lawn mower manufacturers produce their own oils, which will have to be used for replacement, if you want to keep the warranty on the equipment. In addition, the manual provides the general characteristics that the oil must meet. When choosing a replacement fluid, you should be guided by this list. This will allow you to choose an oil that will meet the requirements of the manufacturer as closely as possible.

Many self-respecting manufacturers of lubricating liquids offer their consumers a separate line of products intended for maintenance of garden equipment. If you can choose such a special oil, you should buy it.

  • Shell Helix Ultra is the best among all companies, which represent their products on Russian market. These oils are popular in all countries. For 40 years Shell specialists have been working on the creation of a unique technology of synthetic oil production from natural gas. The resulting product is characterized by an improved composition, which currently has no analogues. The producer adds necessary additives to the base composition, which allows obtaining products with different characteristics. This oil should only be bought from specialist retail outlets, as low-grade counterfeit products are not uncommon.
  • Liqui Moly also offers quality products. The manufacturer produces several product lines, which have different purposes. In this range there are products for the maintenance of garden equipment. Such oils are designed for long-term operation of trimmers and lawnmowers, their technical specifications are developed in accordance with the features of modern machinery and manufacturers’ recommendations.
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The company Liqui Moly adds additives to lawnmower oils, which are necessary to reduce equipment wear and tear and keep the engine clean. The main advantage of such liquids is the environmental friendliness, because they are vegetable-based. Liqui Moly lawn mower oils comply with all environmental standards.

The company Rasenmaher produces a good lubricant of the mineral type, which was specially developed for garden equipment. This tool can be used to service 4-stroke engines with different cooling systems. The substance from Rasenmaher can only be used at plus temperatures. The manufacturer has carefully developed and selected additives for their product. The result of such actions is a wide list of functionalities:

Manufacturers

When choosing an oil, you should pay much attention to its manufacturer. It is better to choose the brand that is advised by the manufacturer of the lawnmower. In the instruction manual of the machine you can find information about the oil to be filled, how often it needs to be changed and recommendations on the choice of working fluid.

Also, many lawnmower manufacturers produce their own oils, which will have to be used for replacement if you want to keep the warranty on the equipment. In addition, the manual provides general characteristics that the oil must meet. When choosing a replacement fluid, you should be guided by this list. This will allow you to choose an oil that will meet the manufacturer’s requirements as closely as possible.

Many self-respecting manufacturers of lubricants offer their customers a separate line of products, which are designed for the maintenance of garden equipment. If it is possible to choose such a special oil, it is necessary to buy it.

  • Among all companies, which present their products at the Russian market, the best is Shell Helix Ultra. These oils are popular in all countries. For 40 years Shell specialists have been working on a unique technology of synthetic oil production from natural gas. The resulting product is characterized by an improved composition, which has no analogues at this time. The manufacturer adds necessary additives to the base composition, which allows obtaining products with different characteristics. This oil should only be purchased from specialized outlets, as low-grade counterfeit products are not uncommon.
  • Liqui Moly also presents high quality products. The manufacturer produces several product lines, which have different purposes. In this range there are products for the maintenance of garden equipment. Such oils are designed for long-term operation of trimmers and lawnmowers, their technical specifications are developed according to the peculiarities of modern machinery and manufacturers’ recommendations.

Liqui Moly adds additive packages to lawnmower oils in order to reduce wear and tear and keep the engine clean. The main advantage of these fluids is the environmental friendliness, because they are made on a plant basis. Liqui Moly lawn mower oils fulfill all ecological norms.

Rasenmaher produces a good lubricant of mineral type, which was specially developed for garden units. This product can be used on 4-stroke engines with different cooling systems. The substance from Rasenmaher can only be used at temperatures above zero. The manufacturer has carefully developed and selected additives for his product. The result of these actions is a wide list of functionalities:

Changing the oil

Lubricant change should be done in a timely manner, according to the maintenance plan listed in the owner’s manual of each mower model. On average, the lubrication efficiency decreases after every 50 hours of operation. When the mower is not in use, the oil filter should be cleaned and the oil changed.

  • turn on the mower and allow the engine to idle for 15 minutes;
  • in the opening of the tank unscrew the plug;
  • put up a tank for collecting the waste;
  • Tilt the unit toward the drain;
  • After draining the used material, screw in the plug;
  • Place the mower on a level surface and open the hole in the top;
  • pour in oil up to the required level, the level is checked with a dipstick;
  • The hole is closed and the plug is screwed on.

The fill volume of most units is up to 500-600 ml.

How much to fill?

Cultivators, mini-tractors and power blocks supplied to the Russian market are mainly equipped with Subaru, BriggsStratton, Honda or their Chinese equivalents. They can be of different capacities and hold different amounts of grease. How to know how much lubricant to pour from a canister, so that a four-stroke engine works in optimum mode, and the lack of lubrication does not erode its parts?

Lubricant consumption rates can be found in the owner’s manual or technical documentation supplied with the machine. The table below shows individual lubricant consumption rates for the most popular engine models.

Required volume, l
Subaru EX21D (7.0 L. с.) 0,6
Subaru EH34B (11.0 l. с.) 1,1
BriggsStratton (8.0 to 13.5 liters. с.) 1,2
Honda GX-390 (8.0 to 13.0 L. с.) 1,1

It is easy to fill the motor lubricant, determining its quantity by the dipstick on the plug. The minimum level is basically limited by the length of the dipstick, and the maximum level is up to the thread of the drain hole. Also you can be guided by looking into the crankcase opening.

As a rule, a single-axle tractor or snowmobile with 6-8 hp engine can hold about 0.6 liters of fluid, in more powerful units. a little over 1 liter of. the most popular filling volume by the manufacturers is 0,6 l. This is the oil rate enough to fill up to the full level of medium-powered motor vehicles, which are most in demand among gardeners and cottage industry owners.