knocking sound from 99 merc 135hp

[bufcopper]

There is a knocking sound coming from engine, did not hear this sound with muffs, but while in the water it was heard. What is it?

 

[Chris1956]

Do you hear the knocking under load? That is usually a bad thing.

Check your timing and link and synch.

 

[bufcopper]

I hear it when I start it and am idling. I do not hear it under load.

 

[bufcopper]

[No message]

 

[bufcopper]

found out it was loose flywheel