What type oil to use in Honda lawnmower?

Answer 1

Honda lawnmowers (and most of their small 4 stroke engines) use a 10W-30 multigrade oil API rated SG or SJ.

After the initial 5 hour change, the oil should be changed every 20 to 25 hours use for almost indefinite engine life, especially in hot or dusty conditions. The factory recommends the initial oil change at 5 hours and then every 50 hours. A 10W-40 is a suitable alternative, especially if used in warmer climates (above 85 degrees F or 30 degrees C).

SG/SJ are older API grades (in fact SG is no longer licensable as at 2012) that contain higher levels of zinc based boundary lubricants, also called anti-wear additives, than the more recent SL/SN API ratings.

If you do not have have access to the official Honda oil, then the next best alternative is the Briggs and Stratton 10W-30 designed for the Vanguard OHV engine series (not the mono grade 30 weight) or, equally, a motorcycle/ motorbike oil designed for an air cooled motorcycle such as a Harley or Ducati, including full synthetics. These motorcycle oils will usually be available in grades 10W-40, 15W-50 or 20W-50. Only use the 20W-50 in summer, or in older engines (over 1000 hours) to reduce oil consumption. These oils contain the higher levels of anti-wear additives and are typically rated SG or SJ.

In an emergency, any automotive oil can be used, but reduce the oil change interval and refer caution below.

Caution: using oil not rated SG or SJ may void your warranty on a newer engine.

note: in a multigrade oil, the first number is the cold ( freezing ) viscosity of the oil equivalent to a mono grade , hence the "W" for winter. The second number is the equivalent mono grade for high(boiling) temperatures, typical of a running engine. The viscosity is how thick or how easily the oil flows, the higher the number, the higher the viscosity. Honey is a high viscosity liquid, water is low viscosity. The viscosity of oil reduces as it's temperature increases - multigrade oils try to compensate by becoming effectively thicker at higher temperatures. During use, a multigrade can thin back to its winter (base) weight which will appear as increased consumption of oil - synthetic oils are much more resistant to this viscosity breakdown.

Answer 2

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