I have a 1998 mariner 225 magnum EFI 2-stroke.
It has a bad stumbling issue.
the serial number is OG655392.
I had it in the shop in 2015 for a new lower unit and tune up, it came back running great.
I ran it maybe 8-10 hours in 2015 after the tune up
Late fall 2015, it started stumbling real...