All 2-cycle engines use a gas & oil mixture to run properly. It needs to be done correctly to avoid damage to the engine of your equipment.
(Gas to oil ratio chart)
What is a 2-cycle engine?
A two-stroke or two-cycle engine is a type of internal combustion engine which completes a power cycle in only one crankshaft revolution and with two strokes, or up and down movements, of the piston in comparison to a "four-stroke engine", which requires four strokes of the piston to complete a power cycle during two crankshaft revolutions. In a two-stroke engine, the end of the combustion stroke and the beginning of the compression stroke happen simultaneously, with the intake and exhaust functions occurring at the same time.
Two-stroke engines often provide high power-to-weight ratio, usually in a narrow range of rotational speeds called the "power band", and, compared to four-stroke engines, have a greatly reduced number of moving parts, and are more compact and significantly lighter in weight. (Wikipedia, Two-Stroke Engine)
2-cycle engines are typically found in chainsaws, line trimmers, leaf blowers and other yard and garden tools.
2-cycle engines do not have a separate oil tank and rely upon the oil mixed with the gasoline to lubricate and cool the engine during operation. Running a 2-cycle with the wrong fuel to oil mixture can cause severe damage to your engine. Running the machine without any oil mixed in the fuel can cause severe damage to your equipment within just minutes. This damage is generally very costly to repair and is usually irreparable.
How do I know if my machine has a 2-cycle engine?
ook at the fuel cap. Most manufacturers will stamp the fuel/oil ratio in the cap.
- Look on the equipment for a sticker or label marking the equipment. (e.g., "Four-cycle" or "No Fuel Mixing").
- Look for an engine oil fill cap. Only four-cycle engines have a separate engine oil reservoir on the back or on the side, with a separate cap (usually yellow or gray) for checking & filling the oil.
- The Operator's Manual will have engine fuel and oil information in it. If you do not have the manual, you can visit the manufacturers web site to download a copy of the manual.
What fuel/oil ratio should I use?
Most newer 2-cycle engines us a 50:1 gas to oil ratio. Older 2-cycle engines may use a different ratio. Two common ratios for older machines is 40:1 and 32:1. These mixtures require more oil per gallon of fuel. Most equipment manufactures will show the required ratio somewhere on the machine. It's very common for this information to be stamped on the gas cap.
If you are unable to find this information on the machine itself you can find it in the owners manual or on the manufacturer's website. Again, it is very important to use the correct fuel to oil mixture in your 2-cycle equipment.
NOTE: The terms "two-cycle" and "two-stroke" are interchangeable, as are "four-cycle" and "four-stroke".