Installed the pre alpha in replace of the blown alpha. Took it out this weekend and did fine until last night. The boat is making a horrific grinding noise and the donkey d1ck from the drive going to the coupler is not moving..and it sounds like that is where my grinding is coming from. Is this the coupler out you think? As soon as I heard the grinding I shut it down so didnt even check to see if it would go into gear. Prop spins free and quiet in neutral..in fwd it clicks and spins clock wise, wont spin counter and in reverse it does the opposite.

Normal.


Sounds like coupler went out. With it in gear, you can't turn the drive at all at the prop by hand? If coupler was completely shot, I'd think the input shaft would spin freely within the coupler splines. Unless it has just enough bite left to be too tight to overcome by hand.

Well since I hear grinding I am thinking its barely hanging on there and on just enough of a bind. I started the boat for about 10 seconds today to listen for the grinding and it was definately at that shaft but the shaft was not spinning..so I am thinking its just barely on there or just rubbing up against it at this point.

as with most mercruiser small blocks the port motor mount nut loosens and as the engine drops and tilts so does the life of the coupler... they do fail for a reason

Thanks! Pulling the motor tomorrow and hoping to be back on the water by the weekend.