Westerbeke 20B Two with non-standard raw water pump

[nesdon]

I'm working on a Cape Dory 30 with a Westerbeke 20B Two engine. The water pump">raw water pump does not seem to match either of the 2 that the Westerbeke catalog shows. The owner replaced the impeller, but it didn't pump, so he assumed the broken blades were clogging the HX, and asked me to help him. I removed the blades form the HX and it still didn't pump, so I pulled the cover and found that the impeller he installed was a much smaller diameter than it should be.

I went to the Westerbeke site to order a new impeller, but the one on this engine has a much different cover arrangement. It only has four thumb screws, not 5 or 6 the catalogs shows, and has a thrust bearing composed of a bronze washer backed up by a UHMW washer recessed into the o-ring sealed cover.

Any idea if this is some sort of alternate cover for a difficult access installation, which this one is, or maybe some sort of aftermarket pump.

[tkeithlu]

Here's one possible route to salvation. The pump may be Jabsco, that being the most popular around. If not, it might still use jabsco impellers. Dig into this PDF and see if you match diameter, thickness, and drive to a Jabsco impeller. You want the impeller to be tight but not really bent at the widest part of the pump enclosure, and to be largely collapsed at the part bearing on the wedge. Good luck with it.

https://www.marine-j.com/pdf/Jabsco-impeller.pdf

[jamhass]

Sounds to me that you might have a "Speed Seal" aftermarket cover on your pump.

Unfortunately, the company (in Britain) had gone out of business and parts are hard to find. The o-ring is available from many sources, but you must (carefully) measure the existing o-ring to get the correct one. With care, you might be able to reproduce the plastic bit from sheet stock.