I brought a 20hp mariner outboard approx 1986 that was in need of a bit of repair (ie. respray, new prop, service etc), and I need some spare parts for it, but everywhere asks for a serial number which I don`t have. Is there any way of getting a number off another part or off the engine so as to age it correctly and be able to get parts for it. Any suggestions appreciated, many thanks Murphoir.......