Getting ready to set my engine back in. Cleaning the coupler up it appeared to have a thin bead of silicone applied to the side that goes to the fly wheel just inside the bolt holes. Is this common practice or could it be the coupler is going bad. Also the bolts I removed are grade five, should they be grade eight.

Thanks

I don't see a need for a sealer on a coupler, if you change bolts, you need to make sure they are a shouldered bolt like the in it now to properly center the plate, personally I don't see a need to change bolts

They are not shoulder bolts. Just Plain 3/8 hex head bolts. Thats what I took out when I removed the engine.

They should be like these, the hole in the coupler is .372 a 3/8 bolt is .356 this will let the coupler move around and not be centered & may cause vibration

Thanks
Definitely not what was in it. I will be calling the local Mercury dealer Monday.

ARP makes them if you have a local speed shop

No local speed shop. Jegs or Summit have them.

McMaster Carr on the bolts, and I would never silicone the coupler.

loctite? hell yes. flywheel bolts too.

Called the local Mercury dealer. They gave me the same part number I found on the Web last night 10-37612. Went to pickup the bolts after work. No shoulder just 3/8 - 16. 1 1/4" hex head bolts grade 5. They were in QuickSilver sealed bag. Counter guy looked around and got a tech involved that's all he has used. He's not sure maybe they come with an HP coupler.