Impeller Kit – Fits Westerbeke Generators (Replaces 33112)
Impeller Kit – Fits Westerbeke Generators (Replaces 33112) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
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Impeller Kit – Fits Westerbeke Generators (Replaces 33112)
Impeller Kit – Fits Westerbeke Generators (Replaces 33112) is backordered and will ship as soon as it is back in stock.
Product Details
This Impeller Kit – Fits Westerbeke Generators (Replaces 33112) is a direct replacement for various Westerbeke generator models from 6.5 kW to 20.0 kW, depending on the specific 60Hz or 50Hz configuration. It's designed to ensure reliable raw water flow for engine cooling.
This kit serves as a direct interchange for several part numbers, including Sierra 23-3302, JMP 7110-01K, Sherwood 10077/10077K, Onan 132-0375/132-0379/132-0498/541-1519, Westerbeke 11764/33100, Crusader 727103, and others.
- Engineered for direct OEM replacement installation.
- Features a durable neoprene impeller with a brass insert and key drive connection.
- Kit includes one impeller, three gaskets, and one O-ring for a comprehensive service.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Sierra | 23-3302 |
| Sierra | 23-2000 |
| Sierra | 23-3310 |
| JMP | 7110-01K |
| Sherwood | 10077 |
| Sherwood | 10077K |
| Onan | 132-0375 |
| Onan | 132-0379 |
| Onan | 132-0498 |
| Onan | 541-1519 |
| Westerbeke | 11764 |
| Westerbeke | 33100 |
| Westerbeke | 33112 |
| Crusader | 727103 |
| Chris Craft | 16.80-90047 |
| Universal | 287439 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This impeller kit is designed for a wide range of Westerbeke marine generators.
| Brand | Model | Rated Output | Frequency | OEM Part No. |
|---|---|---|---|---|
| Westerbeke | 6.5 TWG | 6.5 kW / 4.9 kW | 60Hz / 50Hz | 33112 |
| Westerbeke | 8.0 TWG | 8.0 kW / 6.4 kW | 60Hz / 50Hz | 33112 |
| Westerbeke | 8.5 BTG | 8.5 kW / 6.5 kW | 60Hz / 50Hz | 33112 |
| Westerbeke | 8.5 BTGA | 8.5 kW / 6.8 kW | 60Hz / 50Hz | 33112 |
| Westerbeke | 11.0 TWG | 11.0 kW / 8.5 kW | 60Hz / 50Hz | 33112 |
| Westerbeke | 12.5 BTG | 12.5 kW / 10.0 kW | 60Hz / 50Hz | 33112 |
| Westerbeke | 15.0 BTG/A | 15.0 kW / 12.0 kW | 60Hz / 50Hz | 33112 |
| Westerbeke | 20.0 WTA | 20.0 kW / 16.0 kW | 60Hz / 50Hz | 33112 |
Technical Specs
- Product Type
- Marine Generator Impeller Kit
- Installation
- Direct OEM replacement
- Connection
- Key Drive
- Housing Material
- Neoprene (impeller) with Brass insert
- Housing Color
- Black
- Dimensions
- 57mm diameter × 20mm width (impeller)
- Weight
- 0.14 kg (0.30 lbs) approx. (impeller only)
- Fitting Type
- Key Drive Impeller
- Warranty
- 1 year manufacturer warranty (JMP); Sierra lifetime warranty on materials and workmanship
- Other Technical Attributes
- 12 impeller blades; 12.7mm (1/2") shaft diameter
What’s in the Box
- 1 x Impeller (replaces Westerbeke 33112)
- 1 x Gasket (GAK0041)
- 1 x Gasket (GAK0042)
- 1 x Gasket (GAK0043)
- 1 x O-Ring (ORG0040)
Note: Some applications may not require all items included in the kit.
Installation Notes
- Close the raw water intake seacock before starting work.
- Access the seawater pump assembly on your generator.
- Remove the pump's faceplate screws and cover to expose the old impeller.
- Carefully remove the old impeller using suitable pliers or an impeller puller. Note the direction the blades are bent.
- Clean the inside of the pump housing and the faceplate, removing any old gasket material or debris.
- Install the correct new gasket for your pump model.
- Lightly lubricate the inside of the pump housing and the new impeller with a water-based lubricant or glycerine.
- Insert the new impeller with a twisting motion, ensuring the blades bend in the same direction as the old one.
- Reinstall the faceplate and tighten the screws evenly in a star pattern.
- Open the raw water seacock.
- Start the generator and immediately check for proper water flow and for any leaks around the pump cover.
Troubleshooting & FAQ
How do I know if this impeller fits my generator?
First, check the "Engine & Model Compatibility" table on this page. If your Westerbeke generator model is listed, this kit is a confirmed fit. You can also verify by cross-referencing your existing part number with those in our "Part Number Matrix."
What are the signs of a failing impeller?
Common symptoms include the generator running hotter than normal, a "low raw water flow" alarm, or a noticeably reduced stream of water from the exhaust. Visible signs on the old impeller include cracked, brittle, or missing blades.
How often should I replace my generator's impeller?
As a general rule, impellers should be inspected annually and replaced at least every one to two years, or sooner depending on hours of use and water conditions (e.g., sandy or silty water). Refer to your generator's service manual for specific maintenance intervals.
Why are there multiple gaskets and an O-ring in this kit?
This kit is designed to service multiple generator and pump configurations. Different models use slightly different gaskets or O-rings for sealing the pump cover. Match the new gasket to your old one to ensure a proper seal; you will have parts left over.
Can I install this myself?
Yes, replacing a raw water pump impeller is a common maintenance task for many boat owners with basic mechanical skills and tools. However, if you are unsure about the process, professional installation is recommended to prevent leaks or pump damage.
What happens if I install the impeller with the blades bent the wrong way?
The pump will likely self-correct the blade direction upon the first startup. However, for best practice and to reduce initial stress on the blades, it is always recommended to pre-bend them in the direction of the pump's rotation during installation.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
Payment & Security
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