New boat with drive issue

[scoflaw]

Just bought a 1999 powerquest with a 502 and B1 drive.

​Sight unseen CR deal. Anyways, motor runs but develops a knock, which sounds like a rod, after a couple of minutes. Pull B1 off, knock is gone. PO just changed the drive fluid which looks perfect, of course. Spinning the drive shaft sound s and feels good on the stand. Don't have the special tools for this . Any clue whether it's in the upper or lower. Or the 1st place to start looking with some basic tools

 

[alldodge]

Any clue whether it's in the upper or lower. Or the 1st place to start looking with some basic tools

It might be the U joints, but could also be the shift cable is not adjusted correctly.

Just to make sure, when it was running on muffs the drive was down within trim limits?
When idling with drive on was the prop trying to spin in neutral?
Does the knock go away in gear?