The front of the casing is secured to the pump body with three screws.

Sherwood and Oberdorfer pumps were used interchangeably until August 1996 when Medalist Universal Motors was acquired by Westerbeke.

This pump was used on the engines listed below (and the boats that we are aware used these engines... There could be other combinations as well):
• M-320, (C-27, C-28, C-30)
• M-25XP (Catalina 28, Catalina 30, Catalina 34, Catalina 36)
• M-25XPB (Catalina 28, Catalina 30, Catalina 310)
• M-35B (Catalina 34, Catalina 350, Catalina 36)

Oberdorfer pumps use a carbon bushing as the only bearing. Sherwood pumps have more robust roller bearings, but the roller bearings present a different problem. Proper maintenance is key. Monitor your pump for leaks. If there is enough leakage to be visible, you are already late. Water will begin to be leak into the bearings and the bearings will rust. Wait long enough and the bearings will seize causing catastrophic failure of the pump. Rebuild early and the pump will last over several rebuilds.

Rebuilding your pump will take some time. Unless your boat is on the hard, we suggest you purchase a new pump and a repair kit. Replace the pump to get the boat back into service, then rebuild the pump at your leisure. Now you have a spare pump ready for a quick swap the next time there is a failure.

Sherwood offers another kit that includes even more parts. But it is so all inclusive (it even includes a new shaft) that the price approaches the cost of a new pump. If your shaft is worn, it is time to replace the pump.

• Outside diameter (of a new impeller) 2-7/16"
• Width 7/8"
• Inside diameter 5/8"
• Number of blades: 12

Caution: This kit is to rebuild the newer Sherwood pump (that has three screws to remove to access the impeller. Earlier Universal diesel engines of most any model could have this newer pump as Universal provides an upgrade kit to replace older Sherwood or Oberdorfer pumps that have worn out. Compare your pump to the drawing to ensure you are ordering the correct impeller kit.

This is a project typically completed by an experienced mechanic. If you are a DIY kind of sailor, we suggest you teach yourself how to accomplish a rebuild by studying some online videos before you order. This project requires techniques that are beyond what our tech support staff can teach you over the phone. Information provided by the manufacturer and included with the kit provides tips for those already experienced with this type of repair. A step-by-step rebuild guide is not provided by the manufacturer.