290aq with 5.7. Engine/drive “dry rubbing” noise at idle

Cplacido

Recruit
Joined
Jun 29, 2018
Messages
5
Hey guys .. a little back info.. have a 290aq with the dual prop. Boat starts and runs great and can trim with any issues. Two years ago I replaced the engine and took the trans out and rebuilt it with new pds bearing, open bearings, and filled cavity with grease. I thought I replaced the u joint as well, I’m going to look up the history that would be about 5 years ago for the u joint. I have the tilt meter and usually run it at “5” trim as it seems to overtake the waves better and run at a better rpm.
Problem I’m having is after riding for roughly 45 minutes at plane and coming down to idle I’m having a sort of metallic dry rubbing sound coming from drive area. I have heard what sounds like a dull knock at times also.. the engine seems fine and I can’t hear any noise through there with the stethoscope. I do have a water pump that is going bad ( it wobbles slightly) which I suspect is why my alternator belt has been needing re-tightening twice (belt is also worn as it’s now sitting all the way down in the alternator pulley but still operating correctly). I don’t feel any play in the prop shaft up down or side to side, this season I replaced the output shaft seals to the props. I do have some play when grabbing both props and moving them rotationally towards or away from each other and the play is roughly 1/8 of an inch( not measured but by feel in the water). I’m pretty lost as to this sound, I’m thinking pds bearing again or the u joint… I’m hoping the ujoint lol. When I replaced the engine I had to rebuild the engine cradle and stringers but I measured everything to a T and measured the engine when reinstalling at the rear transmission so it aligned up properly. When under way you can feel vibration at the transom but as I’m always the one driving I don’t know whether that much is acceptable and has always been there due to the engine or if this is new vibration from the drive. New oil in drive this year and also greased the pds bearings.

I live in Michigan so each season is around 4 months, I do the proper maintenance and keep up on the boat. Kinda has me stumped as it’s only really noticeable after a long running, when I first start the boat it doesn’t have this sound.

thanks for the help!
 

Cplacido

Recruit
Joined
Jun 29, 2018
Messages
5
I will when I pull it for the season. I wanted to see if someone had some experience with a related issue and found a solution or if I can do some further diagnostics while it is in the water.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,944
I will when I pull it for the season. I wanted to see if someone had some experience with a related issue and found a solution or if I can do some further diagnostics while it is in the water.
if its grinding, something is wrong.

could be PDS shaft, most likely its u-joints and upper gear box

pull it before you end up spending many many thousands in repair.
 
Top