Mercury 40 4-Stroke Manual page 30

4. Push the dipstick back in all the way, then flip the handle down to lock the dipstick in place.
Reinstall the oil filler cap and hand tighten securely.
a
b
a - Full mark
b - Add mark
FUEL & OIL
c d
c - Dipstick
d - Oil filler cap
24
28813