Short answer: Check your saw's manual first: it gives the fuel mix your saw needs. Phil's crew runs 50 to 1, which is 100 ml of two-stroke oil in 5 litres of fuel. Premix costs more, so professionals usually mix their own, but if you're not confident mixing the ratio, buy premix rather than risk wrecking your saw.
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What Phil says
"Firstly, I'd say check your specifications for your chainsaw. You should get a little booklet if you've just bought one. It'll tell you what fuel mix to put in there. And most of our saws, we run Stihl, so we use 50 to 1. So that'd be like 100 millilitres and 5 litres of fuel."
"If you don't know how to mix the ratios of fuel correctly, then you can buy premix. We don't use it in the professional setting normally because it's kind of expensive. It's a lot cheaper to buy your own fuel, and a lot of guys like to use the more premium fuel in their saws. It is recommended it runs them cleaner and more efficient, so if you don't know, just buy premix because you don't want to get it wrong and wreck your saw."
50 to 1, worked out
| Fuel | Two-stroke oil at 50:1 |
|---|---|
| 1 litre | 20 ml |
| 5 litres | 100 ml |
| 10 litres | 200 ml |
50 to 1 is Phil's crew's ratio for their saws. Use the ratio in your own saw's manual.
Premix or mix your own?
| Mix your own | Premix | |
|---|---|---|
| Cost | Cheaper, which is why pro crews do it | More expensive |
| Risk | You have to get the ratio right | Ratio is done for you |
| Best for | People who run saws every day | Anyone not sure how to mix it |
Getting the mix wrong is how saws get wrecked: too much oil makes it smoke, and no oil at all destroys it (why is my chainsaw smoking?).
40:1 or 50:1?
Use the ratio in your own saw’s manual. Phil’s first step is always to "check your specifications for your chainsaw". His crew runs 50 to 1 because they run Stihl saws.
Free one-page checklist
Phil’s chainsaw troubleshooting checklist
Seven common problems, the checks a working arborist runs first, and when it’s a job for the saw shop. Print it and keep it with your saw.
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From Clogger Answers, episode 1. These are Phil's opinions, based on his professional experience. Always follow your saw's manual and wear the right protective gear.
Phil is a professional arborist based in Invercargill, New Zealand, who runs saws every day with his crew. Clogger makes chainsaw pants and chainsaw chaps.