4-stroke Lawnmower Oil: Which Engine Oil Should I Put In Four-stroke Mowers?

2024 Author: Beatrice Philips | [email protected]. Last modified: 2024-01-09 13:15

Lawn mowers have long taken their place among the necessary equipment among the owners of country and private houses, as well as employees of park management institutions. In the summer, this technique is used quite intensively. For the reliable and durable operation of lawn mower engines, the quality of fuels and lubricants, in particular oils, is of great importance. Oils for 4-stroke engines of this type of gardening machines are discussed in this article.

Why do you need a lubricant?

Gasoline lawn mower engines are internal combustion engines (ICEs), in which the driving force transmitted from the ICE to the working bodies (cutting knives) is generated by the energy generated in the combustion chamber of the cylinder when the fuel mixture is ignited. As a result of the fire, the gases expand, forcing the piston to move, which is associated with the mechanism for further transferring energy to the final organ, that is, in this case, the lawn mower knives.

In the engine, therefore, many large and small parts are mated, which need lubrication in order, if not completely to prevent their abrasion, destruction, wear, then at least to slow down these processes, negative for the mechanism, as much as possible.

Due to the engine oil that enters the engine and covers its rubbing elements with a thin layer of oil film, the occurrence of scratches, scoring and burrs on the metal surface of parts practically does not occur on new units.

But over time, this cannot be avoided, since the development of gaps in the mates still occurs. And the better the oil, the longer the service life of the garden equipment will be. In addition, with the help of high-quality lubricants, the following positive phenomena occur:

• better cooling of the engine and its parts, which prevents overheating and thermal shock;
• engine operation is guaranteed at high loads and with a long time period of continuous grass mowing;
• the safety of internal engine parts from corrosion is ensured during seasonal equipment downtime.

Features of the four-stroke engine

Lawn mower gasoline engines are divided into two groups: two-stroke and four-stroke. Their difference in the way of filling the oil is as follows:

• a lubricant for two-stroke engines must be pre-mixed with gasoline in a separate container and in a certain ratio, thoroughly mixed, and after all this, it must be poured into the fuel tank of the car;
• lubricant and gasoline for four-stroke are not pre-mixed - these fluids are poured into separate tanks and work separately, each according to its own system.

Thus, a 4-stroke engine has its own pump, filter and piping system. Its oil system is of a circulation type, that is, unlike a 2-stroke analogue, the lubricant in such a motor does not burn out, but is supplied to the necessary parts and returned to the tank.

Based on this circumstance, the requirement for oil is also special here . It should retain its properties for a long period, when, as for the lubricating composition of a two-stroke engine, the main quality criterion, in addition to the basic properties, is the ability to burn without a trace, leaving no carbon deposits and deposits.

Selection recommendations

It is best to use a specially designed oil for 4-stroke lawn mower engines in accordance with the ambient temperatures in which the equipment will be used. For example, are quite suitable for four-stroke mowers in terms of their operational parameters specialized grease grades 10W40 and SAE30 that can be used at ambient temperatures ranging from 5 to 45 degrees Celsius.

These oils are recommended as the optimum lubricant for the seasonality of lawn mowers. It is unlikely that anyone would come up with the idea to "start" the lawn mower outside the window at negative temperatures.

In the absence of specialized oils, you can use other classes of oils used for cars. These can be grades SAE 15W40 and SAE 20W50, which are also used at positive temperatures ., but only their threshold is 10 degrees lower than specialized ones (up to +35 degrees). And also for 90% of the available models of four-stroke lawn mowers, an oil of SF composition will do.

The container with engine oil for a four-stroke lawn mower must be marked with the “4T” sign . Synthetic, semi-synthetic and mineral oils can be used. But most often they use semi-synthetic or mineral oil, since synthetic oil is very expensive.

And in order not to guess what oil to fill in the engine of your mower model, it is better to look at the instructions. The required type of oil and the frequency of its replacement are indicated there. It is recommended to use only the types of oils specified by the manufacturer until the expiration of the warranty repair period, in order to maintain the issued warranties . And then choose something more affordable, but, of course, not inferior in quality to branded oils. You should not save on oil quality.

How often do you need to change the lubricant?

As noted above, the operating instructions for garden equipment with a 4-stroke engine must indicate the frequency of oil changes. But if there are no instructions, then they are guided primarily by the number of hours that the equipment has worked (engine hours). Every 50-60 hours worked, you need to change the oil in the engine.

However, in the case when the plot is small and you can process it in no more than one hour, it is unlikely that for the entire spring-summer season the lawn mower will work even half the operating hours of the norm, unless it is rented out to neighbors. Then the oil must be replaced when the equipment is preserved in the fall before the winter period.

Change of oil

Changing the lubricant in a lawn mower engine is not as difficult as changing the oil in a car. Everything is much simpler here. The work algorithm is as follows.

1. Prepare enough fresh oil for replacement. Usually, no more than 0.6 liters of oil is poured into the lubrication system of many lawn mowers.
2. Start the unit and let it idle for a few minutes to warm up the oil so that it becomes more liquid. This promotes better drainage.
3. Switch off the engine and place an empty container under the drain hole from the crankcase to collect the used oil.
4. Unscrew the drain plug and allow all the oil to drain. It is recommended to tilt the device (if possible or advisable) towards the drain.
5. Screw the plug back on and move the machine to a level surface.
6. Open the filler hole on the oil tank and fill it to the required level, which is controlled by a dipstick.
7. Tighten the tank cap.

This completes the process of replacing the lubricant, and the unit is again ready for operation.

What kind of oil should not be filled?

Do not fill a four-stroke lawn mower engine with grease intended for two-stroke analogs (on the labels of oil containers for such engines, the marking "2T" is put). However, you cannot do this and vice versa. In addition, it is unacceptable to fill in the liquid that was stored in plastic bottles from drinking water.

This polyethylene is not intended for storing aggressive substances in it, therefore, a chemical reaction is possible that affects the properties of both lubricants and polyethylene.