The Yamaha F50 Service Manual (officially titled Lit-18616-03-XX or similar, with the specific part number for many recent models) is the factory-authorized document required for proper maintenance, disassembly, repair, and reassembly of the Yamaha F50 4-stroke outboard engine.
Here is the proper, factual response regarding the (for F50TLR, F50TJR, F50ER, F50H, etc., typically 4-stroke models). Topic: Yamaha F50 Service Manual yamaha f50 service manual