4.3 mercruiser knocking

[1976eric]

I recently got my boat back from being winterized oil everything is perfectly normal I noticed a knocking sound coming more from the back of the engine any anyone else have this issue?

 

[1976eric]

Video

 

[alldodge]

Your vid didn't make the trip

 

[Scott Danforth]

Pull the drive to make sure it isnt the U-joints

 

[tank1949]

I recently got my boat back from being winterized oil everything is perfectly normal I noticed a knocking sound coming more from the back of the engine any anyone else have this issue?

did anything freeze?

 

[Scott06]

Pull the drive to make sure it isnt the U-joints

Agreed ujoints or gimbal bearing rusting during winter layup are to possibilities

 

[dubs283]

Trying to get the picture here....knocking sound from engine rear area, first notion would be is drive trimmed in full, second would be as mentioned u joint/gimbal bearing, third would be worn flappers metal to metal contact.

Does noise decrease with rpm?