Unlike regular 4-cycle weed eaters, Stihl has designed a unique engine called the 4-mix engine. This engine does not require you to add oil separately for lubrication as it is added along with the fuel, resulting in more efficient and eco-friendly usage.
When it comes to weed trimmers, many people prefer a 4-cycle weed eater to a 2-cycle one.
This is because it produces more power, making it easy to cut through the weeds and grass while reducing operator fatigue. But for some, differentiating between 4-mix trimmers and 4-stroke ones can be quite difficult.
That’s why we’ve put together this guide to help clear up all doubts on the topic. So, without further ado, let’s begin!
Does Stihl Offer 4-Cycle Trimmers?
Stihl is known for offering products that are incredibly durable, highly efficient, and deliver an unmatched user experience. And its selection of weed trimmers is definitely among the most popular options on the market, including both 2-cycle and 4-cycle trimmers. However, the manufacturer has come up with some unique technologies to differentiate its trimmers from other 4-cycle options.
Stihl uses an innovative 4-mix engine for its trimmers instead of the regular 4-cycle engine used by other brands. This is coupled with the best 2 and 4-stroke technologies to offer certain advantages while delivering a reliable user experience. For instance, these technologies result in much less vibration while the machine is in use, thus helping it last longer while requiring fewer oil changes and making maintenance easier.
What Makes A Stihl Trimmer Different From The Competition?
Unlike some other weed eater brands, Stihl does not manufacture engines for its trimmer line. But the brand manufactures 2 and 4-stroke mix trimmers, which are highly popular options in the segment.
While the 2-stroke Stihl trimmers from the brand operate similarly to competing products from other brands, the 4-stroke mix trimmers are what set the brand apart. These utilize a new type of engine, which the company calls 4-mix, though they operate similarly to standard 4-stroke engines.
The 4-stroke mix trimmers utilize a similar engine piston pattern that includes an intake stroke, a compression stroke, a power stroke, and an exhaust stroke. Similar to standard 4-stroke engines, a 4-stroke mix engine requires an oil and gas mix to operate. However, regular 4-stroke engines use either diesel or gas, while oil is added separately.
In contrast, in a 4-stroke mix engine, oil tanks are not present separately, which is why oil is added to the fuel mix for lubrication purposes.
Understanding A 4-Mix Engine
Stihl has developed the 4-mix engine as a combustion motor that can be used to power a wide range of equipment, including lawn edges, leaf blowers, and weed trimmers. As explained before, this engine works similarly to a standard 4-cycle engine, but the oil needed for lubrication is mixed with the fuel. This makes it similar to a 2-stroke engine.
While originally, Stihl established its reputation by offering 2-stroke trimmers, these were highly inefficient and not compliant with various car exhaust emission standards. That is why the brand decided to shift to its uniquely designed 4-mix engine trimmers.
This engine offers the advantages of both 2-stroke and regular 4-stroke engines, with the fueling technology of the former and the operation of the latter. The 4-mix engine comes with all the components present in a regular 4-stroke engine, such as a spark plug, exhaust and inlet valves and ports, and pushrod passages.
It also has a bypass bore, valve gear, crankshaft and crankcase, piston, and combustion chamber.
Advantages Of The 4-Mix Engine
While the 4-mix engine offers several advantages over both 2-stroke and 4-stroke engines, the biggest one is its limited environmental impact. Both the noise levels and emissions are much lower than in the case of other engines, making such trimmers better for the environment.
Also, the 4-mix engine has a high RPM and a fast start, just like a 2-stroke engine, enabling this string trimmer to get the job done efficiently. And despite its compact form factor, this engine is extremely powerful because of its power-to-weight ratio.
The weight of the engine is reduced since it does not have an oil pump, oil tank, and sump though the engine power output remains uncompromised. Also, a 4-mix Stihl trimmer uses a similar 50:1 gas and oil ratio as used by a 2-stroke engine, though efficiency is much greater.
And unlike regular 4-stroke engines, the 4-mix one does not require oil changes as frequently since they are lubricated from the oil in the fuel mix. This can help avoid situations when you might forget to change the oil, which is quite common in the case of regular 4-stroke engines.
Finally, compared to 2-stroke engines, the 4-mix engine has much lower vibrations meaning that such trimmers will last longer before needing to be replaced.
Working Of A 4-Mix Stihl Engine
There are a few differences in how the 4-mix Stihl engine operates from a regular 4-stroke engine.
The Intake
The induction or intake stroke is the first stage of operation and takes place when the crankshaft drives the piston down the combustion chamber. This causes the fuel mix in the carburetor to enter the chamber, along with air. Due to the presence of a bypass bore in such engines, the fuel mix can easily reach all moving parts in the crankcase and cylinder.
As the piston shifts towards the crankcase, it creates overpressure, which helps pass the fuel mix into the pushrod passages. This allows the mix to reach the combustion chamber for complete lubrication of all parts and maximum fuel utilization. It also allows the lubricant to reach such parts and prevent them from getting damaged through friction.
The Compression
The compression stage involves the closure of both inlet and outlet valves, preventing air or fuel from escaping. Also, the piston shifts up to force the fuel mix and air toward the spark plug.
The Power Stage
The power stage takes place when the cylinder reaches the highest level of compression, forcing the spark plug to create a spark that ignites the air and fuel mix. This leads to combustion and moves the piston down, leading to overpressure. Fuel that is left in the crankcase returns to the combustion chamber.
The Exhaust Stage
As the piston moves to the cylinder bottom, the valve and exhaust port open while the inlet valve remains closed. Gasses and smoke remain in the combustion chamber after combustion and are removed through the exhaust port when the piston moves up again.
The Best Stihl 4-Mix Trimmers
Due to the impressive performance of the 4-mix engine, Stihl is utilizing this technology in almost all of its latest offerings. This means that finding a 4-mix trimmer is easier than ever before, and such products are also the ideal solution for those who are more environmentally conscious.
Among the products worth recommending, the FS 91 R is a fantastic option. It is a commercial brush cutter that is perfect for large-scale projects and comes with a powerful 1.27 horsepower engine. Despite that, it weighs only 5.5 pounds and has an ergonomic straight shaft design for improved maneuverability and smooth operation.
This machine also comes with an easy-to-grip loop handle and a three-step startup and is among the most popular Stihl products.
Another excellent option would be the FS 131 R, which features a 1.9 horsepower engine and is also meant for commercial use. It also offers many features present in the FS 91 R, along with some additional ones. These include the patented IntelliCarb Compensating Carburetor from the brand, which can help control the RPM on disruption of the air intake.
Along with that, there is a fully lined drive shaft, which effectively reduces vibrations and the noise level during operation. And there is a protected choke lever and corrosion-resistant high-tech polymer housing that add to the overall durability and help it withstand greater impact. Last but not the least, it has a shoulder strap that helps distribute the weight more evenly for easier handling.
4 Cycle Weed Eater Stihl Frequently Asked Questions ?
How Does A 4-Mix Trimmer Help In Reducing Harmful Emissions?
Stihl has designed its 4-mix engine in such a manner to ensure that the fuel burns with minimal residues while complying with the Stage II European exhaust limits. This results in low exhaust emissions while reducing waste by-products, making these trimmers a great choice for those looking for eco-friendly options.
Which Is Better, Cub Cadet 4 Cycle Trimmer Or Ryobi 4 Cycle Weed Eater?
When it comes to Cub Cadet 4-cycle vs. Ryobi 4-cycle weed eater, both weed eaters offer some impressive features and deliver a fantastic user experience. That said, both feature different designs and construction, so choosing between them requires considering certain factors.
Despite both companies offering 30cc 4-cycle engines, the Ryobi 4-cycle trimmer comes with a curved shaft, along with safety and kill switches and a curved trimmer head. On the other hand, the Ryobi 4-cycle trimmer comes with heavy-duty construction and can be used with a shoulder strap for easier handling.
What Is The Warranty On A Stihl 4-Mix Trimmer?
A Stihl 4-mix trimmer meant for private, or home use comes with a warranty of two years, while that for professional use has a warranty of six months. For lawnmowers, you get a ten-year warranty on the polymer body and one month on the accessories.
4 Cycle Weed Eater Stihl Final Thoughts
The 4-mix technology developed by Stihl has allowed the brand to develop highly efficient weed trimmers for both home and commercial purposes. It has helped make it easier to keep gardens and lawns clean and reduced the impact on the environment.
At the same time, the reduced need for maintenance involving oil changes further helps improve the user experience. Due to these reasons, the brand is steadily shifting more and more of its offerings to this newer technology, thus offering greater choices to consumers.
And some of the best 4-mix weed trimmers are mentioned here for those looking to replace their old weed trimmer. Just make sure to consider your personal requirements before selecting an option.
With that, it’s a wrap. Goodbye!
