1999 Mercury 175 EFI
Serial# OG870939
Motor has developed a knock, but I don't believe it's in the block...it only knocks while in gear, and doesn't seem to be RPM dependent...its a knock every second or so. I tried to take a video, but with the wind noise it's hard to hear, but I can hear it. In person it's very loud! Boats running great.
It will NOT knock in neutral...it almost sounds like it's in the mid section...
What could it be??