Honda HHH25D Manuel De L'utilisateur page 28

Every 10 hours, check the engine oil level and replenish oil up to the top of the oil
filler neck if the engine is operated for more than 10 hours continuously.
OIL FILLER NECK
LOWER LIMIT
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.
Lubrication oil specifications necessary to maintain the performance of the
emissions control system: Honda genuine oil.
CAUTION:
Using nondetergent oil or 2-stroke engine oil could shorten the engine's
service life.
ENGINE OIL
FILLER CAP
UPPER LIMIT
AMBIENT TEMPERATURE
UPPER LIMIT
25