Honda BF115A, BF130A Outboard Motors Shop Manual., Page 189Get this manual
HONDA BF115A130A
16) Check that the return part at the end of the oil return tube sets on the mounting case securely
If it is hard to set the return part on the mounting case, apply soapy water to the end of the tubeDo not apply oil to the tube121 RETURN PART
17) Insert the oil return tube into the oil return pipe of the cylinder head cover until it contacts the head cover surface