Honda BF50 (5HP), BF5A Outboard Motors Shop Manual 2014, Page 20Get this manual
BF50BF5A
2GEAR OIL
1) Remove the oil level plug and drain plug to drain oil thorough Iy2) Squeeze fresh oil through the drain plug hole until oil begins flowing out of the level plug holeUse the oil tube available as an optional partOil lEVEL PLUG
I GEAR OIL CAPACITY 0.1 (0.21 US pt, O1S Imp pt) I
RECOMMENDED GEAR OIL Mariane SAE 90 by poid gear oil API service classification (GL-4 or GL-5) DRAIN PLUG
3SPARK PLUG
CAUTION: Use only the recommended spark plugs or their equiyalent Spark plugs that have an improper heat range may cause engine damageStandard Spark Plug
I BPR5ES(NGKIW14EPRU(ND)
1) Disconnect the cap and remove the spark plug2) Visually inspect the plugDiscard the plug if it is heavily fouled or if the insulator is cracked or chipped3) Remove carbon or other deposits with stiff wire brush4) Measure the plug gap with wiretype feeler gauge