Honda HHB25 Owner's Manual page 23

Recommended oil:
Use 4-stroke motor oil that meets or exceeds
the requirements for API service classification
SE or later (or equivalent). Always check the
API service label on the oil container to be sure
it includes the letters SE or later (or
equivalent).
SAE 10W-30 is recommended for general use.
Other viscosities shown in the chart may be
used when the average temperature in your
area is within the indicated range.
AMBIENT TEMPERATURE
CAUTION: Using non-detergent oil or 2-stroke engine oil could
shorten the engine's service life.
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