Engine oils have a critical role to play in the workings of a 2-stroke engine and without a good quality engine oil, your engine may only last a very short period of time.
Many think that engine oil only has one job: the lubrication of the moving parts. But they actually do a lot more. When you consider that they’re only added to your fuel in a ratio of 1 part oil to 50 parts fuel, you can understand why we recommend using premium oils; it’s a lot to ask for such a small concentration!
One of the oil’s jobs is to minimise and protect against harmful deposits coking up in the exhaust and slowing the fast flow of exhaust gases from leaving the engine. It also needs to leave the combustion chamber and piston clean so the engine can “suck, squeeze, bang and blow” in the most efficient way possible. After all, a clean engine will more likely produce more power! Find out more about how a 2-stroke engine works here.
When you see the moving components of the engines, you can see why a good quality engine oil is required. As these components can move at a rapid rate of up to 15,000 rpm, the oils are used to minimise wear to the engine by providing lubrication to moving parts.
Learn how a STIHL 2-MIX Engine works:
The oil also needs to be clean burning so that the spark plug continues to spark over and over again, and to have a long working life. The spark plug plays an important role in the engine as it ignites the fuel and oil mix so it’s important to make sure it’s protected.
2-stroke engine oils also have to work across a range of engine types with large variances in temperature and rpm. Petrol hedge trimmers operate with a relatively low 5000 rpm and a temperature of around 150 degrees at the spark plug, while chainsaws operate with an rpm of up to 15,000 and temperatures of 300 degrees at the spark plug.
Engine oil quality also plays a big part in preventing carbon build-up around the valves of 4-MIX petrol engines. It’s important to use STIHL HP Super or HP Ultra oil with STIHL 4-MIX engines to reduce the likelihood of poor running behaviour and the need for a trip to a servicing STIHL dealer.
The engine oils also have to protect the engine from corrosion and keep the crank case clean (the lower half of the engine) to allow the fuel mix to circulate and components to move freely. That’s why we have spent years developing and refining STIHL engine oils to suit all applications, from consumer tools through to professional use.
We have three different types of oils available in the range; STIHL HP, HP Super (Semi-synthetic, low smoke) and STIHL HP Ultra (Fully Synthetic), a selection that we like to call our good, better and best offering!
STIHL oils are formulated with a base oil and then have special additives on top to give them certain beneficial properties. The base oil is a mineral oil in the case of HP and a fully synthetic oil in HP Ultra.
These special additives give the oil a certain viscosity or lubricity, as well as giving anti-wear properties and reducing carbon deposits and corrosion. In STIHL HP Super, the additive polyisobutene leads to reduced smoke from the exhaust. In the case of HP Ultra, the synthetic additives are biodegradable.
All of these STIHL oils can be used with E10 fuel. As E10 fuel has a short shelf life, we do recommend mixing 2-stroke fuel in small quantities to avoid wasting engine oil.
You can see the difference in the piston after 500 running hours between STIHL oils, and a conventional, poor-quality oil. As you can see, an engine using HP Ultra looks almost new!
If you don’t want to worry about mixing your own fuel, we offer our own pre-mixed, premium alkylate fuel, STIHL MotoMix. STIHL MotoMix is long lasting, high-quality fuel combined with HP Ultra oil for best engine performance.
You can find out more about STIHL engine oils at your nearest STIHL Approved Dealer, or ask us any questions in the comments below.
Paul HicksPaul has worked for STIHL for six years and is responsible for the range of STIHL products that is sold here in Great Britain, which means he definitely knows his stuff when it comes to all things STIHL.
Why is hp ultra a lower rating than hp super? Ultra being ISO -L-EGB whereas super is rated ISO-L-EGD. Surely super is the superior oil here, is it purely for the environment reasons ultra is recommended?
Hi, thanks for your comment. HP Super is a semi-synthetic, low smoke, low ash oil which is a very good all round performer. HP Ultra is our most premium, fully synthetic oil with the best lubrication, cold start properties and is also bio-degradable. HP Ultra is our best oil in all JASO categories except for “Low Smoke” . HP Super fulfils all the demands of JASO FD including low smoke which is why it appears to have a higher certified rating. The L-EGB and L-EGD have the same requirements as JASO FB and JASO FD respectively, with an additional test for piston cleanliness.
Thanks, STIHL GB
what should be done to winter rise a Sthil 800 leaf blower for cold Minnesota winters when it just sits in the garage for 6 months?
Hi, thanks for your comment. We have a blog post specifically on storing your petrol power tools for winter here with more information on it: https://blog.stihl.co.uk/store-petrol-power-tools-winter/
The most important thing is to drain the tool of all fuel before storing it. Thanks very much, STIHL GB
Hi, can you advise me regarding the best oil to use in my old FS350 brushcutter? I’ve always used regular red Stihl HP oil.
I probably only use it 3 or 4 times a year these days. I always run it out of fuel before storing, but I sometimes have some mixed fuel left over, and sometimes I have to discard it due to age. I read that your green HP Super can be stored for longer – is this suitable for older 2-stroke machines like mine?
I also heard that synthetic oil can damage many plastics, including fuel hoses etc. Does this mean that HP Super can damage hoses, diaphragms etc. especially in an older machine?
Thanks
Hi Chris, thank you for your comment. An FS 350 should be run using a high quality two stroke oil. STIHL recommends running its lubricants at a mixture of 1:50 for optimum performance. STIHL HP Super is a semi synthetic low smoke oil and is specifically designed for 4 mix engines and machines with mixed lubrications regimes. Our Ultra 2 Stroke Engine oil is fully synthetic and best used for periods of use under the most demanding of conditions. Fuel degradation can happen when using fuel from petrol stations due to the levels of ethanol present. We would recommend using STIHL MotoMix which is ethanol free and has almost no olefins or aromatic compounds. This fuel is premixed with STIHL Ultra 2 Stroke and can be stored for up to 5 years. STIHL MotoMix has been rigorously tested and causes no issues with all 2 stroke , 2 Mix and 4 Mix engines. This would be a good choice of fuel to switch over to if you are only using your machines periodically. Hope this helps. Thanks, STIHL GB.