Two-stroke vs four-stroke: how upkeep differs

Two-stroke and four-stroke engines need different attention, and the rules for one don't fit the other. Mixing them up with oil or fuel mix gets expensive.

• Four-stroke: oil lives in the crankcase. Check the level on a warm engine through the sight glass or dipstick, and change it per the owner's manual.
• Two-stroke: find out how oil is delivered. Some engines have a separate oil tank, others run on premixed fuel. Take the ratio only from the manual.
• On a two-stroke with an oil tank, never let it run dry: without oil the engine seizes quickly.
• On a four-stroke, check valve clearances at the interval in the manual. A two-stroke has no valves, but carbon buildup in the exhaust and silencer cuts power.
• Check the air filter on both types, and on a two-stroke also the spark plug: its colour shows whether the mixture is right.
• If you lack experience, leave piston and cylinder work to a workshop.