2005 225HO
E225FHLSOB
5014110
I was fishing on Sunday and all of a sudden about 1/2 through the day it sounded like a knock at about 45 mpg and 4700 RPM. I came off plane and idled around for a little while, then put the boat back on plane and heard the sound again, so I idled 5 miles back to the ramp.
Got home, pull the plugs out, they all looked in good condition. Did a compression test all cylinders are 115 to 120.
Did a static test with the injectors and ignition, and it all seems to be working correctly.
Looking for advice, what to check next?