Impeller Vanes for Sherwood Raw Water Pump

[lrclough]

Every year when I inspect the impeller vanes on my Sherwood water pump">raw water pump (Westerbeke 58 engine using a Sherwood R30G-1 pump), about a third of the impeller vanes are gone.

I replaced the pump a couple of years ago, and the new pump is no better than the old one.

Is this normal?

[noelex 77]

No this is not good. The impeller should not loose any blades. Any lost material needs to be found as it will clog up the cooling passages.
A very short impeller life suggests it is running dry, not priming properly, the raw water pump has a rough or worn surface, the impeller is the wrong type, the cooling water inlet is not always below the surface, there is a blockage in the exhaust elbow etc. You need to find the cause.

[Blue Stocking]

Do you check that the vanes are retarded for the correct rotation direction when fitting a new impellor?