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

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

This impeller kit is specifically designed for Westerbeke marine generators ranging from 3.3kW to 15.0kW, equipped with the 33636 sea water pump. It is a direct replacement for models manufactured prior to March 2004 that feature the irregular-shaped pump cover.

This component is a direct replacement for Westerbeke part numbers 034440 and 34440, as well as Sierra part number 23-3307. It is critical to verify your pump housing style before ordering; this impeller will not fit pumps with a round cover and O-ring seal made after March 2004.

• Material: Durable neoprene for reliable raw water circulation
• Installation: Fits raw water/sea water pumps on specified generator models
• Kit Includes: Impeller, gasket, and installation screws

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 generator is off and the sea cock is closed to prevent water ingress.
2. Locate the sea water pump, Westerbeke part number 33636.
3. Remove the screws holding the irregular-shaped cover plate on the pump.
4. Carefully remove the cover and the old gasket. Note the orientation of the impeller blades.
5. Using pliers or an impeller puller tool, grip the center hub of the old impeller and pull it straight out of the housing.
6. Clean the inside of the pump housing, removing any debris or old gasket material.
7. Lightly lubricate the new impeller with a water-based lubricant or dish soap.
8. Install the new impeller by pushing it into the housing while turning it in the direction of engine rotation to bend the blades correctly.
9. Place the new gasket onto the pump housing, aligning it with the screw holes.
10. Reinstall the cover plate and tighten the screws evenly in a crisscross pattern. Do not overtighten.
11. Open the sea cock. Start the generator and check for leaks and proper water flow.

Troubleshooting & FAQ

Q: How do I confirm this impeller fits my generator?
A: This impeller is only for Westerbeke generators made before March 2004 that use sea water pump #33636 with an irregularly shaped cover. If your pump has a round cover that seals with an O-ring, this part will not fit, and you will need impeller kit 48500 instead.

Q: What is the difference between this impeller and the one for newer pumps?
A: The primary difference is the pump housing it fits. This impeller (034440) is for the older style pumps with an irregular cover and a flat gasket. Newer pumps (post-March 2004) use a round cover with an O-ring and require a different impeller kit (48500).

Q: How often should I replace the water pump impeller?
A: For preventative maintenance, it is recommended to inspect your impeller annually and replace it every 1-2 years or every 200-300 operating hours, whichever comes first. This interval can vary based on usage and water conditions.

Q: What are the signs of a failing impeller?
A: Common signs include engine overheating, reduced water flow from the exhaust outlet, visible cracks or missing blades on the impeller, and a stiff or brittle texture to the neoprene material.

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.