Oil case and method for manufacturing oil case

A method for manufacturing an oil case of an outboard motor, the oil case being provided below an internal combustion engine and storing a lubricating oil of the internal combustion engine, the oil case including:

• an oil chamber that stores the lubricating oil;
• a lead-in path that guides, to an upper side, cooling supply water that has been taken in from outside of the outboard motor;
• a lead-out path that guides, to a lower side, cooling discharge water that has cooled the internal combustion engine;
• a main exhaust path that guides an exhaust gas of the internal combustion engine to the lower side;
• and
• a subsidiary exhaust path that guides the exhaust gas during low-speed rotation of the internal combustion engine,
• the method comprising:
• during manufacturing, disposing, in a cavity of a mold configured to mold the oil case, a lead-out path-dedicated core configured to form the lead-out path, a main exhaust path-dedicated core configured to form the main exhaust path, a subsidiary exhaust path-dedicated core configured to form the subsidiary exhaust path, and a gap formation-dedicated core extending along the main exhaust path-dedicated core, and
• injecting the cavity with molten material, in a state in which the lead-out path-dedicated core, the main exhaust path-dedicated core, the subsidiary exhaust path-dedicated core, and the gap formation-dedicated core are disposed.