Gasket Set- What is this O ring?

Hello All.
I'm hoping I can get help identifying a couple of these O-rings pictured. They cam in an OEM gasket set. I cant find any reference of the content (OEM: 43779A87) even here on iboats.

One is 3" in Dia and pretty thick and the other is 2"dia.

I have found that there is redundancy in this set if you order say a fuel kit or water pump kit. But anyway, I like to find a spot for these O-rings as long as I've completely taken apart the power head.

A side question: I noticed some gaskets have a bead of sealant and other do not. Is that to say the other gasket can simply go on dry? Other concern is if should I put a sealant on the cylinder block in addition to the cork gaskets that seem to just run the length of the block.

Thanks for any help!

Re: Gasket Set- What is this O ring?

Here ya go....

Re: Gasket Set- What is this O ring?

Lots of kits fit lots of different motors.
Some have a small difference and use a different part.
So they include a bunch of parts that don't fit all the applications.
So you end up with extra parts. J