Sherwood M71 water pump cam wear

[fryedaze]

Changed impellers and cams. I was very surprised at the wear on the cam. It is probably the first time it was replaced in 5100 hrs.View attachment 94256View attachment 94257

 

[Jay N]

Hi Dave.


5100 hrs on a M71 cam is very good service - Longer than I have seen.


Here's excerpts from my service log:


[FONT=&quot]- [/FONT][FONT=&quot](1)[/FONT][FONT=&quot](1)[/FONT][FONT=&quot] SW pump #1 – 3912019 (Sherwood M71, 1987) [/FONT][FONT=&quot](in service 1988 to 4/03)[/FONT][FONT=&quot][750.0 replaced impeller and shaft seal, 1461.0 new impeller, 2324.8 new backing plate and removed from service][/FONT][FONT=&quot] Total: 3253 hrs service, keep as working spare. (still has original cam, note hour meter failure - add 928 hrs to above numbers. Purchased boat 11/97.)[/FONT]
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[FONT=&quot]-- SW pump #2 – 3912019 (Sherwood M71, 1987) [/FONT][FONT=&quot](in service 4/03 to 12/15)[/FONT][FONT=&quot][New impeller: 2324.8, 154.0, 889.1, 1521.5, 2343.3. Turned backing plate at 889.1 hrs. New backing plate and cam at 1521.5 hrs. Removed from service at 3157.7] [/FONT][FONT=&quot]Total: 3815.1 hrs service, thrown away due to housing wear. (NOTE: Second failed hour meter, add 3902 hrs to numbers after 2324.8)[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]- [/FONT][FONT=&quot](1)[/FONT][FONT=&quot](in service 12/15 at 3157.7 hrs)[/FONT][FONT=&quot] SW pump #3 – 3912019 (Sherwood M71, 10/13) [/FONT][FONT=&quot][New impeller: 3945.4, 4471.7] [/FONT][FONT=&quot]Total: 2014.3 hrs service at meter reading of 5172.0 (just over 9000 hrs total on the engine at this time)[/FONT]
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[/FONT]

[FONT=&quot]You'll notice that SW pump #2 seems to have failed early. I suspect a slight machining error that created extra wear. The other two pumps still have original cams/backing plates.
[/FONT]​

 

[High Wire]

Yep. Normal wear item.

 

[fryedaze]

Worn cam

 

[High Wire]

I have seen the fingers completely gone on one side. Always check the cam on an impeller change out.