Please help me with two questions on replacing the impeller in a lower
unit of my Mercury 1995 115hp 4-cyclinder outboard:

1. Do I need to put any lubrication in the inside surface of the
sealing ring on top of the water pump housing? My understanding is
that the drive shaft goes right through the sealing ring, and the
inside surface of the sealing ring is supposed to be tightly contacting
the drive shaft. I would assume that we need some kind of lubrication
on that surface. But the instruction that comes with the Mercury
Impeller Repair Kit only talks about cleaning the dirt grease and oil
from the drive shaft before putting the sealing ring onto the drive
shaft; it doesn't say anything about lubricating the sealing ring.
Likewise, the SELOC repair manual also doesn't say anything about
lubricating that surface in the sealing ring. On the other hand, the
same SELOC repair manual explicitly says that we need to lubricate the
two oil seal rings at the bottom of the water pump base; this is odd to
me considering the fact that both the sealing ring on top of the water
pump house and the oil seal rings at the bottom of the water pump base
have close contact with the same drive shafe; if lubrication is good
for the oil seal rings at the bottom, lubrication should also be good
for the sealing ring at the top, right? Why do we lubricate one but
not the other? Should I lubricate that sealing ring at the top? What
kind of lubricant should I use? Should I use "Mercury 2-4-C Marine
Lubricant with Teflon" (multi-purpose lubricant) or another special
lubricant?

2. Do I need to put any gasket-sealant on the gaskets of the water
pump housing? Neither the instruction that comes with the Mercury
Impeller Repair Kit nor the SELOC repair manual says anything about
putting sealant on the gaskets. Do I have to use sealant, or am I
better off using sealant than not? I guess the common gasket sealant
that I find in marine supply store should be good enough, right? Do I
need to put sealant on both sides of the gasket?

Thanks in advance for any suggestion.

Jay Chan