4.3L mercruiser alpha 1 loud screaching noise

[BlueVIP]

1993 Monterey with a 4.3L merc alpha 1. Boat starts and seems to run fine. After running it for a little while then sitting with it turned off for a little bit. When I start it again it will make a loud screaching noise sounds like belts to me but not sure. Read somewhere online it could be alternator bearing or Gimbal bearing. I thought the gimbal bearing made a growling noise? Any help would be appreciated.

 

[alldodge]

Yes gimbal growls, Alt bearing or belt squeals

Remove the belt a feel the bearings spinning each pulley

 

[BlueVIP]

Had my mechanic change oil today and he tightened up the belts. How tight should the belts be? Thanks

 

[Scott Danforth]

depends if its a multi-vee (serpentine) or a traditional v-belt. if a v-belt, the specific series has a spec

 

[vetting]

How long does the noise last when you start it up? Its it worse when its damp out?

 

[BlueVIP]

It lasts maybe 30 seconds. It has quit now with the belts being tightened up. It tried to do it yesterday after running it while pulling the kids on the tube.