Sierra 3002 Johnson/Evinrude Impeller

The Sierra 3002 (18-3002) Impeller is a six-blade replacement water pump impeller for compatible vintage Johnson, Evinrude, and OMC outboards. Installed inside the lower-unit water pump housing, it draws cooling water through the gearcase and circulates it through the engine. Directly replaces Johnson/Evinrude OEM impeller numbers 375638 and 775518. Included in Sierra 18-3203 impeller kit and 18-3377 water pump kit.

Parts Desk Insight Best Use

The Sierra 18-3002 covers a broad range of vintage Johnson and Evinrude outboards (1035 HP, approx. 19491978), but these engines frequently changed water pump designs without any change in horsepower rating. Matching OEM number 375638 or 775518 from the engine parts diagram is far more reliable than relying on the horsepower decal or approximate year. The number stamped on the removed impeller is the strongest fitment confirmation.

Replace every 23 seasons or 200 hours regardless of visible wear. On vintage engines that may have sat for years, inspect the rubber for hardening and brittleness a common failure mode on stored outboards that can cause sudden cooling loss.

Key Specifications

• Sierra part number: 18-3002
• Six flexible neoprene blades
• Approximate outside diameter: 2-3/4 in.
• Approximate depth: 7/8 in.
• Approximate shaft opening: 3/4 in.
• Included in Sierra 18-3203 impeller kit and 18-3377 water pump kit
• Impeller only housing, wear plate, key, and seals not included
• UPC: 030999237125

Engine Compatibility

Associated with vintage two-stroke Johnson and Evinrude outboards, generally 1035 HP, approx. 19491978, including selected 10, 15, 18, 20, 25, 30, and 35 HP models. Multiple lower-unit and water pump designs were used during this period always verify by complete engine model number, production year, and OEM impeller number before ordering.

Alternate Part Numbers

• Sierra: 18-3002 / 118-3002
• Johnson/Evinrude/OMC: 375638, 0375638, 775518, 0775518
• Related J/E reference: 777829
• GLM Marine: 89650
• Mallory Marine: 9-45215, 9-45215-10

Installation Notes

Lower-unit removal is required to access the water pump. 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 3083 (18-3083) Johnson/Evinrude Impeller
• Sierra 3090 (18-3090) Johnson/Evinrude Impeller
• Sierra 3001 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.