DF115 Knocking

[jemako3]

Took Boat out the other day for the first time this year and at higher rpm's I am getting a knocking noise. Pulled the cover off motor and could not hear anything on the top end. Any Suggestions what this might be? Major/Minor. Oil looks clean and no alarms or signals on tach.

[keakar]

it might just be worn out and starting to go bad, what year is it and how many hours do you think you have on it?

I think if it were in the piston/crank area you would still hear it but quieter at lower speeds so I suspect its something in the valves but anytime you hear a knocking sound from the engine it needs to be looked over by a mechanic before you do more serious damage to it.

to trace it down use a hard object like a wooden dowel or screwdriver handle and cup it to your ear while touching the other end to the motor. this lets you hear the inside of the engine and may let you track the sound to where it is coming from

[artdf175]

how old is the fuel?
this would be the first place I would inspect.
if you have a small spare tank and hose .. try fresh fuel to see if knocking goes away..

[jemako3]

2005 Motor with only about 300 hours on it. Will try fuel to see. Using ethanol free fuel but its about seven months old.

[jemako3]

Took it Suzuki technician and found out today that it was spark knock. Thank god. But still cant believe it. Was using ethanol free gas and it was only about 5 months old.