Bravo III Vibration

[msd58]

I was heading out of my no-wake-zone and when I was getting boat up on plane, I trimmed drive down to get the bow down (trim position was still in same spot from previous run) as I normally do when I heard/felt a vibration when I trimmed the drive down. It only happens then. Never did it before. 7.4 Bravo III 28' Cruiser 450 hours single engine boat. Any thoughts?

 

[Bondo]

Ayuh,.... Any noise/ sounds with this vibration,..??

Motor,..?? Drive,..?? Whole boat,..??

 

[msd58]

There is faint rumbling sound during the vibration The vibration is coming from rear of boat. I would not say from the motor but the drive. As I stated it only happens on the down travel of the outdrive to trim all the way in to get bow down. The trim travel in minimal during the occurrence.

 

[alldodge]

Going all the way down and tight against the stops leans me think something in the drive is loose or worn. When the drive is not tight against the stops, any slop may not be felt or heard do to wear. I would pull the drive plug and check gear lube, then pull drive and check U joints, bell housing and pins

 

[msd58]

I had drive pulled in winter, pressure tested, fluid changed and u joints inspected. All were fine. Mechanic said that I had wear in the bushings in the gimbal ring. Possibly other bushings in other areas perhaps the bell housing but I can't remember exactly. I know he mentioned the gimbal ring for sure.

 

[msd58]

I checked drive fluid level this AM. A-OK level has not moved since spring commissioning. I tired to duplicate the vibration this AM with boat in the slip and in gear. No sound or vibration.

 

[alldodge]

Vibrations in the drive while in gear is either the drive, U joints, gimbal or prop.

 

[msd58]

Vibrations in the drive while in gear is either the drive, U joints, gimbal or prop.

As I stated only vibration that is felt when drive is trimmed down last few inches. Then and only them. Thru all rpm ranges including WOT and trim up travel there is no vibration.