Sierra 18-3399 Water Pump Kit with Housing, Replaces OMC 0396933, Fits 50 HP 1986-88 Outboards

The Sierra 18-3399 is a complete water pump kit built for 50 HP outboard engines from the 1986-88 model years. Unlike a basic repair kit, this version includes a full water pump housing, so it covers everything needed to rebuild the cooling system's water pump in one purchase rather than requiring the housing to be sourced separately.

Inside the kit are the core wear components that fail over time and cause overheating: the impeller (18-3368), wear plate (18-3343), and water pump housing (18-3336), along with the oil seal (18-2705), wear plate gasket (18-2709), grommet (18-3337), and O-ring (18-7134) needed to seal the assembly. Mounting hardware is included as stainless steel bolts (18-3365 and 18-3369) for corrosion resistance in a marine environment. The housing has a white finish. Sierra kits are assembled to meet or exceed the original equipment manufacturer's specifications, and the impeller compound is formulated for this specific application.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3399
• Product Type: Water Pump Kit
• Includes Housing: Yes
• Weight: 1.06 pounds
• Color: White
• Material: Stainless Steel (mounting bolts)
• Included Components: Oil Seal 18-2705, Wear Plate Gasket 18-2709, Water Pump Housing 18-3336, Grommet 18-3337, Wear Plate 18-3343, Stainless Steel Bolts 18-3365, Impeller 18-3368, Stainless Steel Bolts 18-3369, O-Ring 18-7134
• Fitment: 50 HP outboards, 1986-88
• UPC: 030999753649

Fitment

• 50 HP outboards, 1986-88

Replaces (OEM)

• 0396933
• 0439077
• 9-48207

Frequently Asked Questions

What is included in the Sierra 18-3399 water pump kit? The kit includes an oil seal (18-2705), wear plate gasket (18-2709), water pump housing (18-3336), grommet (18-3337), wear plate (18-3343), stainless steel bolts (18-3365 and 18-3369), impeller (18-3368), and O-ring (18-7134), giving you everything needed for a complete water pump rebuild.

Does the 18-3399 kit come with a housing? Yes, the 18-3399 kit includes the water pump housing (18-3336), unlike housing-less versions of the kit.

What engines does the Sierra 18-3399 fit? This kit fits 50 HP outboards from the 1986-88 model years.

What OEM part numbers does the 18-3399 water pump kit replace? It cross-references to Evinrude/Johnson 0396933 and 0439077, and Mallory 9-48207.

What impeller comes in this kit? Impeller 18-3368 is the impeller included in the Sierra 18-3399 water pump kit.

What is the difference between kit 18-3399 and kit 18-3385 for the same engine? Both kits fit 50 HP outboards from 1986-88, but 18-3399 includes the water pump housing while 18-3385 is the equivalent kit without a housing, intended for buyers reusing their existing housing.

How much does the water pump kit weigh? The Sierra 18-3399 water pump kit weighs 1.06 pounds.

What material are the mounting bolts made of? The mounting bolts included in kit 18-3399 are stainless steel for corrosion resistance in marine use.

Does the kit include an oil seal and gasket? Yes, oil seal 18-2705 and wear plate gasket 18-2709 are both included in the 18-3399 kit.

What color is the water pump housing? The water pump housing included in the 18-3399 kit is white.

Is the Sierra 18-3399 a genuine Sierra part? Yes, 18-3399 is a genuine Sierra part number, not an aftermarket clone, and is manufactured to meet or exceed original equipment specifications.

What is the UPC for this water pump kit? The UPC for the Sierra 18-3399 water pump kit is 030999753649.