Full Power Plus Water Pump Kit Evinrude/Johnson 20-35HP (1980‑UP) — Neoprene Impeller & Housing

This Full Power Plus water pump kit replaces the Evinrude/Johnson 20–35HP water pump assembly and housing (parts 393630 / 0393630 / Sierra 18-3382) for reliable cooling system rebuilding.

Keep your vintage or later-model Evinrude and Johnson outboard running cooler by replacing worn cooling components with a complete rebuild kit. This kit includes the neoprene impeller, housing, gaskets, seals, mounting hardware and related pieces engineered to restore water flow and reduce the risk of overheating. Parts fit a range of 20, 25, 30 and 35 horsepower engines from 1980-up, with specified compatibility for 1985 and later models and select 1998–2001 units.

What parts are included and why do they matter?

The kit supplies everything needed to rebuild the water pump and housing so you can replace deteriorated components in one service. Using modern neoprene for the impeller and durable metal alloys for the housing improves longevity compared with older, brittle parts.

• Neoprene impeller (395289) for consistent water flow and flex resistance
• Pump housing (393632) and pump cup (328751) for correct alignment
• Wear plate, impeller gasket (325537), seals, O-ring and install bolts for a complete reseal
• Key and hardware to secure the assembly without extra parts hunting

How do I know this fits my outboard?

Compatibility covers Johnson/Evinrude 20hp, 25hp, 30hp and 35hp models in the stated years; verify part numbers and model year before ordering. Check your engine’s service manual or the original pump part number to confirm match with 393630 / 0393630 / Sierra 18-3382.

• Fits 20hp models 1985 and later
• Fits 25hp models 1985 and later, including 1998–2001 Johnson/Evinrude
• Includes the common OEM cross-reference numbers for verification

How difficult is installation and what tools are needed?

Installation is a standard mechanical task for someone with basic marine repair skills and common hand tools. Removing the lower unit, swapping the impeller and housing, and reassembling requires care to align seals and torque bolts to spec; professional service is recommended if you’re uncertain.

• Requires lower unit removal and basic mechanic’s set (sockets, screwdrivers, torque wrench)
• Follow engine manual torque values and shaft key installation steps
• Replacing the impeller seasonally or after signs of wear prevents heat-related damage

What materials and durability features does this kit provide?

Components are manufactured from modern neoprene and robust metal alloys selected for corrosion resistance and long service life in marine environments. The design aims to withstand repeated wet/dry cycles and the abrasive conditions inside cooling passages.

• Neoprene impeller resists cracking and fatigue better than older compounds
• Alloy pump housing resists warping and corrosion under normal use
• Complete gasket and seal set minimizes leaks and ensures proper pressure

Who this is for: Boat owners, small-boat mechanics and marine technicians who maintain Johnson or Evinrude 20–35HP outboards and need a complete, reliable water pump rebuild kit. It’s ideal for seasonal maintenance, emergency repairs, or restoring performance on older engines when original pump parts show wear or failure.