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Water Pump Base Plate

S

SWTraver

New member
I've replaced my impeller and water pump over the years, but I never knew there was a "base plate" to be replaced also, and one was never included in any of the pump kits I ever got, whether OEM or Sierra. How often does this need replacing and why isn't this part included in the pump service kits?? Thanks for your answers!
 
It has been always a seperate item for Alpha drives as it does not need replacement as often as the impeller and housing.

The right way to know how often is by doing a pressure check before refilling drive when you do that part of your service.
Otherwise It would be based on hours of use which varies a lot.
I personally replace them every time i do an impeller and housing if I know the history of the boat. Typically every 4-5 years based on fresh water use only.

Salt water use may require impeller and housing replacement more often but as long as NO water has been found in gear oil I would say 4-5 years is a good period of time for water pump base replacement

If someone brings me a new to them, boat I replace it as a baseline for there new to them boat.
 
Just remember,
As an outdrive ages the groove created by the seal lip(s) get deeper on the shaft it is sealing to. Therefor its hard fo predict a "lenght of time" for use/replacement.

A new shaft with a new base with new seals could last many years vs a 20-30 year old shaft with grooves may last 2-3 years (as an example)
 
Thank you kghost. The shaft in my unit is from 1988! When I perform the service in a few weeks I will examine the shaft to see if there are grooves present. I would think a stainless shaft wouldn't get many groves from a plastic base but I'll check and report back. Thanks for your response!
 
It is not plastic on stainless steel.

The base has two seals back to back that seals, oil and water that ride on shaft and a Oring that seals to cavity.

Your missunderstanding of what is what and what it does is part of your not understanding fhe base assembly.
 
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