?'s re: Groove worn in driveshaft from water pump

rattlin

Cadet
Joined
May 9, 2010
Messages
17
Hi everyone. This is my first post on this forum. I've lurked here for a month or so trying to learn about an overheating problem I've had. I think that I've got that figured out thanks to all the great knowledge found on this forum, but now I've come to a point where I need to ask a question (I did search the forum first)

1994 90HP Evinrude

Along the way, I've pulled the water pump apart. The motor was long overdue for an impeller change, and it was done by a shop in the past, so I decided to do it myself this time. Upon removing the pump housing, I see there is noticeable wear on the drive shaft about 5/8 inch above the top of the impeller. The groove does not correspond to the top of the stainless steel cup, but appear to correspond to a place where the plastic of the pump housing closes in on the shaft about 1/2 inch above the cup. When I place the unattached pump housing back on the shaft (but not completely back over the impeller, which is still in it's original place) there is some slop between the housing and the shaft.

As I examine a parts diagram online, such as

http://www.boats.net/parts/search/BRP/EVINRUDE/1994/E90TLERC%201994/GEARCASE/parts.html

I see there is an O-ring located above the steel cup (#78 in diagram), but it's not clear exactly where it will go. Currently I see no evidence of an O-ring in that area of my pump, although I've yet to pull the cup out of the housing. I would think something is supposed to be in there to seal water from exiting the top of the water pump housing along the drive shaft.

Can anyone tell me more specifically where this O-ring should be located? I'm hoping not on the worn area of the shaft.

Thanks!
 

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: ?'s re: Groove worn in driveshaft from water pump

#78 in the diagram goes into a groove in the housing and forms a seal between the metal liner and the housing, it does not touch the driveshaft. Not all of the water pumps made over the years are exactly alike.
 

rattlin

Cadet
Joined
May 9, 2010
Messages
17
Re: ?'s re: Groove worn in driveshaft from water pump

Thanks! So it appears there is nothing to seal against the shaft in the top section of the waterpump.
 

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: ?'s re: Groove worn in driveshaft from water pump

No. #72 in your diagram seals the tube that the driveshaft is in from the exhaust but that's it.
 

jasper60103

Commander
Joined
Sep 18, 2008
Messages
2,055
Re: ?'s re: Groove worn in driveshaft from water pump

I had a similar question when I replaced my water pump. #78 was eliminated from the new water pump kits. When the water pump fills with water it forms a seal. F_R explained it to me, but I forgot the details. Anyway, the bottom line is #78 is no longer needed with the new water pump housing.
 

rattlin

Cadet
Joined
May 9, 2010
Messages
17
Re: ?'s re: Groove worn in driveshaft from water pump

I had a similar question when I replaced my water pump. #78 was eliminated from the new water pump kits. When the water pump fills with water it forms a seal. F_R explained it to me, but I forgot the details. Anyway, the bottom line is #78 is no longer needed with the new water pump housing.

Thanks! I found your previous thread:

http://forums.iboats.com/showthread.php?t=366106&highlight=water+pump+seal


I understand it a lot better now. Thanks to you all!
 

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: ?'s re: Groove worn in driveshaft from water pump

You may understand it better, but you do need the seal (#78) in the new V4 waterpump.

I think they number it #10 in the installation instructions, but it is still there.
 

Attachments

  • 5001595 5001594_3.jpg
    5001595 5001594_3.jpg
    67 KB · Views: 2

rattlin

Cadet
Joined
May 9, 2010
Messages
17
Re: ?'s re: Groove worn in driveshaft from water pump

Thanks! I've ordered the OEM kit spec'd for my motor, so hopefully it's got everything it needs, including that O-ring.
 
Top