5 Things to Know About 50:1 Chainsaw Fuel Mix

Stick with 50:1 Almost all modern two-stroke chainsaws from Stihl, Husqvarna, Echo, and others use a 50:1 ratio—one part oil to 50 parts gasoline, or about 2.6 ounces of oil per gallon. Check your owner’s manual, but this is the standard today.

Too much oil causes problems Using too much oil fouls spark plugs, creates heavy smoke, and builds up carbon in the exhaust and piston. It won’t destroy the engine quickly, but it will run poorly and gum things up over time.

Too little oil is the real danger Inadequate lubrication causes metal-on-metal contact, scoring the cylinder and piston, overheating, and eventually a seized engine. Replacing the top end costs far more than a bottle of quality oil.

Use synthetic oil for air-cooled engines A good synthetic two-stroke oil designed for air-cooled engines provides better protection and cleaner combustion than cheap conventional oil. Don’t use outboard motor oil.

Mix in a gas can, not the saw’s tank Pour the oil into a gas can first, add gasoline, then shake well before filling the saw. Mixing directly in the tank leads to uneven ratios and poor lubrication.