Tutor Auto Water Pump Kit for Johnson & Evinrude 20–35 HP — 393630 Replacement Impeller Kit with Gaskets & Hardware

The Tutor Auto 393630 water pump kit is a complete, direct-fit impeller replacement designed to restore cooling performance on Johnson and Evinrude 20–35 HP outboards.

Keep your older outboard engine running reliably by replacing the failing impeller and related components before overheating or cooling loss occurs. This kit replaces common Johnson/Evinrude part numbers (393630, 393509, 391636, 0393630) and Sierra 18-3382, and contains the neoprene impeller, housing parts, gaskets, seals, bolts and the small wrench needed to perform the job. It’s intended for a range of 20–35 HP Johnson and Evinrude models from the late 1970s through the early 2000s—check your engine’s model year and part references against the compatibility list to confirm fit.

Which engines and years will this water pump kit fit?

This Tutor Auto kit is formulated to replace factory water pumps on multiple Johnson and Evinrude 20–35 HP outboards across different production years. It covers specific 20, 25, 30 and 35 HP applications listed by OEM part cross-reference.

• Compatible with Johnson/Evinrude 20 HP (1985 and later where specified)
• Covers Johnson/Evinrude 25 HP (1985 and later) and 25 HP Commercial (1998–2001)
• Fits Johnson/Evinrude 30 HP (various 1980–1983 models) and 35 HP (1980–1982)
• Replaces OEM numbers 393630, 393509, 391636, 0393630 and Sierra 18-3382

What components are included and why they matter?

The kit supplies every internal wear part needed to rebuild the water pump chamber so you don’t need multiple orders or improvised fixes. Using all-new mating surfaces and seals restores the water pathway and reduces the risk of leaks.

• Neoprene impeller (395289) — flexible vanes for reliable water flow
• Pump housing (393632) and pump cup (328751) — replace worn casings
• Wear plate, gasket (325537), O-ring and seal — ensure a tight, leak-free fit
• Bolts and install wrench — hardware included for straightforward installation

How durable and accurate is this replacement compared to OEM?

Tutor Auto supplies a high-quality aftermarket kit manufactured to match OEM dimensions and function. While not an original OMC-branded part, materials and tolerances are selected to meet or exceed factory performance for longevity and proper fit.

• Neoprene impeller compound chosen for wear resistance and flexibility
• Precision-machined housings for correct clearances and pump performance
• Complete gasket and seal set to prevent leaks and maintain pressure
• Direct-fit design minimizes modification or additional parts

How difficult is installation and what should I prepare?

Installation is a moderate DIY job for someone with basic mechanical skills and standard hand tools. The kit includes the install bolts and wrench, but you should have service manual guidance, a clean workspace, and common tools to complete the replacement correctly.

• Allow time to drain lower unit water and remove the old pump housing
• Follow torque specs and sealant guidance from your engine manual
• Inspect driveshaft, bearings, and cooling passages while the pump is removed
• Test for correct water flow at startup before launching

Who is this for: The Tutor Auto 393630 water pump kit is aimed at boat owners, marine mechanics, and DIYers who maintain older Johnson and Evinrude outboards in the 20–35 HP range and want a complete, value-minded pump rebuild set. It’s especially useful for seasonal maintenance, routine 100-hour service intervals, or when symptoms—low cooling flow, cavitation, or overheating—indicate the impeller and related components need replacement. Verify engine model and OEM part numbers before purchase to ensure compatibility.