Snapped Raw Water Pump Shaft after 50 hrs

Irie308

Well-Known Member
May 28, 2013
2,577
CT
Boat Info
2004 420 DB, GHS Hydraulic Lift
Garmin 8600/Garmin 1222 plus
AB Mares 10 VSX with 30 hp Tohatsu
Engines
Cummins 450C 8.3 L Turbocharged
Last spring I made the mistake of buying a raw water pump from WM. It was in a pinch so I was just glad they had one in stock. I believe its the sierra brand. This season after 50 hrs of use the shaft snapped on me while cruising. We were at the beginning of our 1 week vacation and fortunately I was able to get back up and running in a few hours with the aid of a rebuilt spare. The more i think about it the more annoyed I get that the shaft just broke. The bearings seems fine and there was no sign of leaks. It looks as if the metal just failed. I've called WM and they said i should have purchased the extended warranty. I'm going to call Sierra on this next, if nothing else just to make them aware of their poorly made product. So I post this partly to vent as well as a PSA about this product.
rawater pump.jpg
rawater pump2.jpg
 
I have never seen a sheared raw water pump shaft before. I'm sure Sierra would be interested. If I was their supplier.....I would want to take a close look at that shaft.

Send a letter to this guy: Benson Smith. He is CEO and Chairman of the Board of Teleflex. They own Sierra. I find that is the only way to get attention on a matter like this.
 
I like it when they said "you should of bought the extended warranty" made me laugh!. Like the extended warranty would do anything for it
 
I just took a closer look at your photo of the shaft......those look like vibration marks. Was the impeller loose on the shaft? Those are strange marks for 50 hours of use.
 
Good thing you had a spare on board!

Dale
 
I just took a closer look at your photo of the shaft......those look like vibration marks. Was the impeller loose on the shaft? Those are strange marks for 50 hours of use.
Hmmm...will take a closer look. Pump is at home but the impeller is on the boat.
 
i'm going to send my old pumps to a guy to rebuild..........
 
So I went to WM and spoke to one of the managers who is very knowledgeable and much more helpful than most. He gave me a contact at Sierra to speak to. Long story short, Sierra replaced the water pump free of charge and stated that such a failure should never happen. They are going to examine the old one to see why it failed. For now the replacement will remain a spare as I don't completely trust it.
 
That is great news. I have never seen anything like that with a raw water pump. I suspect a harmonic disturbance caused the shear but the guys at Sierra will get it figured out. It is also possible it was a defective shaft that already had a crack in it. It is good to see Sierra backs their products.
 

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