Need Info on Replacing Impeller in Lower Unit
 

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

Need Info on Replacing Impeller in Lower Unit
 

wrote in message
oups.com...
1. Do I need to put any lubrication in the inside surface of the
sealing ring on top of the water pump housing?

You can pre-lube it with dishsoap or KY - avoid petrolium based stuff. Same
goes for impeller.
After you run it - the water will wash all away and your final and only lube
will be the water.

2. Do I need to put any gasket-sealant on the gaskets of the water
pump housing?

NO - just make sure all is clean.

-W

Need Info on Replacing Impeller in Lower Unit
 

Clams Canino wrote:
wrote in message
oups.com...
1. Do I need to put any lubrication in the inside surface of the
sealing ring on top of the water pump housing?

You can pre-lube it with dishsoap or KY - avoid petrolium based stuff. Same
goes for impeller.
After you run it - the water will wash all away and your final and only lube
will be the water.

2. Do I need to put any gasket-sealant on the gaskets of the water
pump housing?

NO - just make sure all is clean.

-W

That damned Kentucky jelly is good for a LOT of great things!

Need Info on Replacing Impeller in Lower Unit
 

Clams Canino wrote:
wrote in message
oups.com...
1. Do I need to put any lubrication in the inside surface of the
sealing ring on top of the water pump housing?

You can pre-lube it with dishsoap or KY - avoid petrolium based stuff. Same
goes for impeller.
After you run it - the water will wash all away and your final and only lube
will be the water.

2. Do I need to put any gasket-sealant on the gaskets of the water
pump housing?

NO - just make sure all is clean.

-W

Thanks for the explanation. Now, I understand why I don't need to put
any oil to lubricate the sealing ring at the top of the water pump
housing. The idea of water being a lubricant didn't come to my mind
until you point this out. No wonder the instruction manual asks me to
clean all the oil (in addition to cleaning out dirt grease) from the
drive shaft before putting the sealing ring onto the drive shaft. This
makes perfect sense now.

The SELCO repair manual asks me to put a thin coat of multiple-purpose
lubricant on the inside surface of the water pump housing. I guess
this is to ease the initial hand-turning of the impeller to fit inside
the housing and is not intended for long term. In that case, I should
use dish-soap as what you have suggested or put as thin a coat of
multiple-purpose lubricant as possible.

As of not putting sealant on gasket, I guess the extra thickness of the
sealant may leave too much room inside the housing, and that is the
reason why you don't suggest using sealant, right? This also makes
sense to me. I guess I should not put something where it is needed.
Thanks for the info.

Jay Chan