Purpose of this seal

[Sheff 69]

What is the purpose of the rubber/metal seal at the side of the water pump impeller?
Why isn't it just a metal to metal joint?

[Sheff 69]

[Masonmobilemarine]

Keeps exhaust water out of incoming cold water

[TownsendsFJR1300]

Looks like my lower unit!

(it is):

[pstephens46]

Looks like my lower unit!

(it is):

Key way too clean. Next time use a torch and dynamite to remove key.

[boscoe99]

Although Yamaha shows the metal clip being installed in a certain orientation it really does not matter. Install the clip in any way that makes the most sense to the installer.

[TownsendsFJR1300]

Key way too clean. Next time use a torch and dynamite to remove key.

Actually, look up and slightly to the right of the key way. Some very slight scars from a screw driver and hammer "assisting" removing the last key..

[Sheff 69]

Quote Originally posted by TownsendsFJR1300
Looks like my lower unit!

Yes Sir it is. Why waste a really good photo to better explain my question.
But why not a metal to metal joint?
What would be the consequences of a bad seal at that location?
My rubber is bad.

John

[pstephens46]

The assumption is to keep exhaust turbulence away from the water pump. Turbulence that could affect cooling water flow. $5-10 part?

[99yam40]

rubber should seal better over time, and easy to replace when it starts falling apart.

probably had problems with corrosion in that area way back and this was a easy and cheap fix( Just my opinion)

[Sheff 69]

Thanks, it was curiosity only as to why a rubber seal.
Anyway this summer I have to pull the lower unit to check the impeller and change the oil, so I'll replace it.

John