I'm a ford senoir master tech and have torn down an older 2 stroke merc.my questions this see lower topic stalling 90 hp and knocking well the knocking seem like a piston slap.comp is 130 all .can I have good comp and still have piston noise,I bought some gallon baggies a few small ice chests and the book.I have studied book now can I remove the cyl head to inspect pistons or do i have to remove powerhead also were can I get good qulity parts for cheap. and lastly any good tips I should know.please help.its a 2003 90 hp eltpo