You never mention if this noise is related to turning as well? PS may be your issue? Please get manual to look up these parts/names. Having knowledge of them will help you out in the long run. Trust me! Did you examine OD's lube????? Get a spline/coupler alignment tool and check engine coupler for alignment, AND after spinning motor over 180 degrees. Perhaps something (stringer or transom) has sagged and hard to see. Also, make sure (difficult), if alignment is off, that the flywheel or coupler has not come loose. You might be able to insert crow bar and try to put pressure on coupler. Almost impossible on my bravos. Lack of room... You will need an OD mount/stand or a place to rest OD. Put into gear and have friend lock down prop spline (vise grips work pretty well or have him hold prop stationary with wood block) so it does not easily move. On the u-joint end insert large screw driver into u-joints and later yoke and apply pressure and look for movement on u-joints or yoke. Sometimes the 4 ends of a u-joint don't get grease into them. It has happened to me on a truck. If no movement, then check for roughness within OD as you rotate drive spline. You might have an OD having issues. Water in bearings don't play together well.
