Honda BF50 (5HP), BF5A Outboard Motors Shop Manual 2014, Page 131Get this manual
BREATHER FILTER REASSEMBLY: 1) Push breather filter down into the slit of the breather chamber as shown until it comes level with the breather cap gasket installation surface of the breather chamber
PUSH DOWN
CYLINDER HEAD SIDE
SHORTER
INOTICE I
Be careful that the filter is not placed on the rib of the breather chamber2) Push the cylinder head side of breather filter down securely until it touches the bottom of the breather chamberInstall breather filter B, aligning its end with the end of breather filter A