Honda BF8, BF9.9 and BF10 Outboard Motors Shop Manual., Page 50Get this manual
2ENGINE OIL Oil Level Check
1) Run the outboard motor in an outboard test tank with the
water at least inches above the anti-ventilation plateAllow the engine to warm up to normal operating temperature
Engine exhaust contains poisonous carbon monoxide gas that can cause unconsciousness and deathIf the engine must be running, make sure the area is well ventilated2) Stop the engine and remove the engine coverHold the
outboard motor upright
UPPERLIMIT
3) Remove the dipstick and wipe it clean
4) Insert the dipstick all the way in, then pull it out and check the oil levelCheck the engine oil condition, change the engine oil if it is stale or contaminated with foreign material
[21 LOWER LIMIT
5) If the oil level is low, remove the oil filler cap and add the recommended engine oil to reach the upper limit mark on the dipstick