This year we purchased a 2005 Sylvan 8420 pontoon. The engine is a 2003 Mercury 60ELPTEFI, it runs good but only gets to 5100 rpm at around 18-19 mph. The engine has 400 hours of low speed cruising. The prop is a 48-77338A45 11P. The engine will Rev to 6000 rpm in neutral. It has had recent...
