Honda UMC425 Owner's Manual page 23

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
AMBIENT TEMPERATURE
may be used when the average temperature
in your area is within the indicated range.
CAUTION:
Using nondetergent oil or 2-stroke engine oil could shorten the engine's
service life.
20