I bought a 1988 Mako 17 with a 1988 Johnson 120 past summer.My first boat. Soon after I noticed metal shavings on the magnetic plug of lower unit. A local Johnson service rebuilt the lower unit.After 4-5 Hrs of boating I did check the filler plug and find, fine metal fuzz stuck to it. Could that be normal after rebuilding ? Thak You for this forum! I think I am hooked.