Sierra 3083 Johnson/Evinrude Impeller

The Sierra 3083 (18-3083) Impeller is a six-blade replacement water pump impeller for compatible Johnson, Evinrude, and OMC outboard engines. Installed inside the lower-unit water pump housing, it draws cooling water through the gearcase and circulates it through the engine. Replaces Johnson/Evinrude OEM references 377230 and 777213. Included in Sierra water pump kits 18-3325 and 18-3376.

Parts Desk Insight Best Use

Older Johnson and Evinrude engines frequently share the same horsepower rating while using completely different water pump assemblies. Matching this impeller to OEM number 377230 or 777213 from the engine parts diagram is far more reliable than relying on the horsepower decal alone. This impeller covers a wide vintage range (late 1950s1978) across 3555 HP applications, so confirming the full model number and production year is essential before ordering.

Replace every 23 seasons or 200 hours regardless of visible wear. Impeller vanes harden and lose flexibility before showing obvious damage, reducing cooling flow without warning.

Key Specifications

• Sierra part number: 18-3083
• Six flexible impeller blades
• Fits compatible J/E/OMC 3555 HP two-stroke outboards (late 1950s1978)
• Included in Sierra water pump kits 18-3325 and 18-3376
• Impeller only housing, wear plate, key, and seals not included
• UPC: 030999315359

Engine Compatibility

Commonly associated with compatible two-stroke Johnson and Evinrude outboards using OEM impeller 377230 or 777213:

• 35 HP applications
• 40 HP applications (approx. 19601970)
• 50 HP applications (approx. 19711978)
• 55 HP applications (approx. 19711978)

Always confirm by complete engine model number, production year, gearcase configuration, and OEM water pump diagram. Do not order by horsepower or approximate year alone.

Alternate Part Numbers

• Sierra: 18-3083 / 118-3083
• Johnson/Evinrude/OMC: 377230, 0377230, 777213, 0777213
• Related OEM reference: 777821
• GLM Marine: 89660
• Mallory Marine: 9-45209, 9-45209-10

Installation Notes

Lower-unit removal is required to access the water pump assembly. During service: inspect the pump housing, wear plate, key, seals, and driveshaft; remove any broken impeller fragments from cooling passages; lubricate the new impeller with clean soapy water or approved assembly lubricant; rotate the driveshaft in its normal operating direction while seating the housing over the blades. Confirm strong cooling-water telltale flow before operating under load. Never operate the outboard without an adequate cooling-water supply.

Related J/E Impellers

• Sierra 3050 (18-3050) Johnson/Evinrude Impeller
• Sierra 3051 (18-3051) Johnson/Evinrude Impeller
• Sierra 3043 (18-3043) Johnson/Evinrude Impeller
• Sierra 3090 (18-3090) Johnson/Evinrude Impeller
• Sierra 3001 Johnson/Evinrude Impeller
• Sierra 3002 Johnson/Evinrude Impeller
• Sierra 3055 Johnson/Evinrude Impeller
• Sierra 3058 Johnson/Evinrude Impeller
• Sierra 3059 Johnson/Evinrude Impeller
• Sierra 31041 Johnson/Evinrude Impeller

Compatible Water Pump Kits

• Sierra Marine Water Pump Kit 18-3380 Johnson/Evinrude 4075HP
• Sierra Marine Water Pump Kit 18-3390 Johnson/Evinrude 85300HP V4/V6

Always confirm fitment against your engine service manual and full model/year before ordering.