Water Pump Impeller Kit – Fits Westerbeke Marine Generators 3.3-15.0kW (Replaces 034440, 34440)

Water Pump Impeller Kit – Fits Westerbeke Marine Generators 3.3-15.0kW (Replaces 034440, 34440)

This water pump impeller kit is designed for Westerbeke marine generators from 3.3kW to 15.0kW manufactured prior to March 2004 equipped with raw water pumps that have an irregular-shaped cover. Please verify your pump model before ordering.

It serves as a direct replacement for Westerbeke part numbers 034440 / 34440 and Sierra part number 23-3307.

• Fitment Note: Only compatible with pumps using an irregular-shaped cover (pre-March 2004). Not for pumps with a round cover.
• Impeller Material: Durable Neoprene for reliable performance in raw water applications.
• Complete Kit: Includes the impeller, gasket, and mounting screws for a full-service replacement.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below.

Technical Specifications

Package Contents

• 1 x Water Pump Impeller (034440)
• 1 x Pump Cover Gasket
• 2 x SS Hex/Slot Screws

Installation Guide

1. Ensure the engine is off and the sea cock is closed to prevent water from entering the vessel.
2. Locate the raw water pump on the generator. You may need to remove panels for access.
3. Unscrew the bolts holding the pump cover plate in place and remove the cover.
4. Carefully remove the old impeller. If it's stuck, use two screwdrivers or an impeller puller tool to gently pry it out.
5. Clean the inside of the pump housing and the cover plate, removing any old gasket material or debris.
6. Place the new gasket onto the pump housing.
7. Lubricate the new impeller with a small amount of water-resistant grease or dish soap, then insert it into the housing, bending the blades in the direction of the pump's rotation.
8. Reinstall the pump cover and tighten the screws in a star pattern to ensure an even seal. Do not overtighten.
9. Open the sea cock. Start the engine and immediately check the pump cover for any leaks.

Troubleshooting & FAQ

Q: How do I know if this impeller fits my Westerbeke generator?
A: This impeller is only for Westerbeke generators made before March 2004 that use a sea water pump with an irregular-shaped cover (pump model 33636). It will not fit newer pumps with a round cover and O-ring seal, which require impeller kit 48500 instead.

Q: What are the signs my impeller needs replacing?
A: Common signs of a failing impeller include the engine overheating, reduced or no water flow from the exhaust outlet, visible cracks or missing blades on the old impeller, and excessive pump noise.

Q: How often should I replace the impeller?
A: For preventative maintenance, it is recommended to inspect your impeller annually and replace it every 1-2 years, regardless of appearance. If your generator runs in silty or sandy water, more frequent replacement may be necessary.

Q: OEM vs. Aftermarket?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.