Hardin Gen. 4, Rev. 2 Sea Pump Master Rebuild Kit 

Master Rebuild Service Kit - For Gen. 4, Rev. 2 Hardin Stainless Pumps - Mercury Replacement

This master kit is a rebuild service kit for the Hardin Marine stainless impeller housing 625-4178 and stainless pump 625-4110 . This kit comes with new wear plates , O-rings, seals, impeller and retaining clip.

Which Rebuild kit do I need?

Gen. 4, Rev. 1 pumps have a 1/8" drain plug in the rear housing and a slotted front wear plate.
Gen. 4, Rev. 2 pumps have no drain plug and a solid front wear plate.