The Role of Engine Oil in a Stihl 2-Stroke Engine

Without a good quality engine oil, your engine won't last very long. Engine oils are added to your fuel in a ratio of 1 part oil to 50 parts fuel so it's recommended to use premium oil.

A clean engine will most likely produce more power. As well as providing lubrication, the oil's job is to reduce and protect against harmful deposits building up in the exhaust and slowing the fast flow of exhaust gases from leaving the engine.

The components can move at a fast rate of up to 15,000 rpm, so the oil minimises wear to the engine by giving the moving parts lubrication. You can see why a good quality engine oil is needed when you see the moving components.

For the spark plug to have a long working life and to spark over and over again, the oil needs to be clean burning. It's important to protect the spark plug as it ignites the fuel and oil mix.

2-Stroke engine oils have to work across different engine types which can vary in temperature and rpm quite a lot.

• Petrol hedge trimmers operate with a 5000 rpm and a temperature of around 150 degrees at the spark plug.
• Chainsaws operate with up to a 15,000 rpm and a temperature of 300 degrees at the spark plug.

The quality of engine oil helps prevent the build up of carbon around the valves of 4-Mix petrol engines. It's important to remember to use STIHL HP Super or HP Ultra oil with STIHL 4-MIX engines to prevent potential poor running behaviour.

Engine oils also need to protect the engine from corrosion and keep the crank case clean. This will alow the fuel mix to circulate and components can move freely.

The three types of oil available from Stihl are:

• STIHL HP
• HP Super (Semi-synthetic, low smoke)
• STIHL HP Ultra (Fully Synthetic)

Check out our other blog post where we list all these oils in a range of sizes in detail!

All of these oils can be used with E10 fuel. This fuel does have a short shelf life so Stihl recommend mixing 2-stroke fuel in small quantities to avoid wasting engine oil. They do offer a pre-mixed, premium alkylate fuel 'Stihl Motomix' which is long lasting, high quality fuel combined with HP Ultra oil.