Gas-to-Oil Ratio on a Lawn Boy

Advantages, Disadvantages and Care of Two-Cycle Engines

• Two-cycle engines are both cheaper and lighter and produce usable energy every revolution; four-cycle engines produce energy only every second revolution, although they have a higher power output. However, because two-cycle engines do not have dedicated lubrication systems, you must add two-cycle-engine oil to the gas to lubricate their crankshafts. It's important that you add it in the proper ratio of gas. Typically, users add a certain number of ounces of the two-cycle oil to a gallon of gas to ensure accurate measure.

The Cycle Count

• An engine's cycle, or stroke, number describes the pistons moving inside the engine’s cylinders. Two-cycle engines complete a burn-and-vent cycle every two strokes, which is one revolution of the crankshaft, or one down stroke plus one up stroke. When the fuel ignites, the burst of energy pushes the piston downward, and the next injection of fuel is compressed on the upward stroke of the piston. The following down stroke will be the first of the next two-stroke series. In four-cycle engines, the first stroke following the ignition of the fuel conveys power to the crankshaft, the second stroke is a return stroke, the third stroke expels the exhaust gases and the fourth stroke is the return stroke that compresses the next fuel to be burned.

Fuel and Oil Ratios

• Lawn Boy products requires 4 ounces of two-cycle oil to be added to each gallon of gas, which creates a 32:1 ratio; 32:1 is the normal mix for Lawn Boy products. If you add 8 ounces of two-cycle oil to a gallon of gas, you create a 16:1 ratio. Adding 2.6 ounces of two-cycle oil to a gallon of gas creates a 50:1 ratio.

Typical Ratio for Lawn Boy Products

• All Lawn Boy Generation II products, being those manufactured in 1970 or later, use a 32:1 ratio. Two-cycle oil is typically sold in containers calibrated by the ounce; 1 gallon of gas must have 4 ounces of oil added to create a 32:1 ratio. If your container of two-cycle oil is measured in milliliters, one gallon of gas must have 125 milliliters of oil added to create a 32:1 ratio.

Lawn Boy’s Recommendations for Gas

• Lawn Boy recommends the use of a high quality gas sold by a recognized petroleum company. The octane rating should be 87, or as near as it as possible. Gas stored without a stabilizing additive should be used within one month; even with stabilizer, however, the gas should be used within six months. Stabilizer should be mixed into the gas on the day of purchase.