Water Pump Impeller Kit – Fits Onan 4.0-7.5 KW Generators (Replaces 131-0386, 131-0257)
Water Pump Impeller Kit – Fits Onan 4.0-7.5 KW Generators (Replaces 131-0386, 131-0257) is backordered and will ship as soon as it is back in stock.
Worry-free returns
Worry-free returns
Shop with confidence. If you’re not completely satisfied, eligible items may be returned within the return window, provided they are unused and in original packaging.
If the return is due to our error or a defective item, we’ll make it right.
Please contact us before returning any item.
Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
International delivery times may vary due to customs processing.
Tracking information will be provided once your order ships.
Water Pump Impeller Kit – Fits Onan 4.0-7.5 KW Generators (Replaces...
Water Pump Impeller Kit – Fits Onan 4.0-7.5 KW Generators (Replaces 131-0386, 131-0257) is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Impeller Kit is an aftermarket replacement designed for Onan MCCK and MDJE series marine generators, covering models in the 4.0 to 7.5 KW power range. It's engineered specifically for water pumps that use a 4-screw cover plate.
It serves as a direct replacement for multiple Onan and aftermarket part numbers, including 131-0386, 131-0257, and Globe 1015.
- Direct OEM-spec replacement for straightforward installation.
- Includes a 6-blade CR neoprene impeller and a matching 4-hole gasket.
- Impeller features a durable brass insert and a D-shaped shaft profile.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Onan | 131-0386 |
| Onan | 131-0257 |
| Onan | 0131-0257 |
| Onan | 170-3172 |
| Globe | 1015 |
| Globe | P/N 01-12-1610 |
| BCO | 1015 |
| GCS | 1015 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
Designed for Onan MCCK and MDJE series generators using a water pump with a 4-screw cover plate.
| Brand | Model | Rated KW | OEM Part No. | Notes |
|---|---|---|---|---|
| Onan | MCCK | 4.0 | 131-0386, 131-0257 | 4 screw cover pump models only |
| Onan | MCCK | 6.5 | 131-0386, 131-0257 | 4 screw cover pump models only |
| Onan | MDJE | 6.0 | 131-0386, 131-0257 | 4 screw cover pump models only |
| Onan | MDJE | 7.5 | 131-0386, 131-0257 | 4 screw cover pump models only |
Technical Specs
- Product Type
- Water Pump Impeller Kit
- Installation
- Direct OEM replacement
- Impeller Material
- CR Neoprene with Brass Insert
- Shaft Type
- D-shaped
- Shaft Width
- 9.5 mm (3/8")
- Impeller Width
- 19 mm (3/4")
- Impeller Diameter
- 57 mm (2-1/4")
- Number of Blades
- 6
- Gasket Type
- 4-hole
- Gasket Part Number
- 131-0210
- Weight
- 90.7 g (3.2 ounces)
- Package Dimensions
- 121 × 90 × 31 mm (4.76 × 3.54 × 1.22 inches)
What’s in the Box
- 1 x Water Pump Impeller (Replaces 131-0386)
- 1 x Gasket (Replaces 131-0210)
Installation Notes
- Disconnect the generator's battery and close the raw water intake seacock.
- Access the water pump and remove the cover plate screws.
- Carefully pry off the cover and note the rotational direction of the existing impeller blades.
- Remove the old impeller using pliers or an impeller puller tool.
- Clean any debris or old gasket material from the pump housing and cover plate.
- Lightly lubricate the new impeller and housing interior with glycerin or soap (do not use petroleum grease).
- Install the new impeller, bending the blades in the direction of normal engine rotation.
- Place the new gasket on the clean housing face.
- Reinstall the cover plate and tighten the screws evenly in a star pattern to ensure a proper seal.
- Re-open the seacock and reconnect the battery.
- Start the generator and immediately check the pump and hoses for water leaks.
Troubleshooting & FAQ
How do I know if this impeller kit fits my Onan generator?
This kit is designed for Onan MCCK and MDJE series generators (4.0 to 7.5 KW) equipped with a water pump that has a 4-screw cover plate. Please verify your model and original part number against the compatibility tables on this page before ordering.
What are the signs of a worn or failing water pump impeller?
Common symptoms include the engine overheating at idle or load, a noticeable reduction in water flow from the exhaust outlet, and visible cracks, tears, or missing blades upon a physical inspection of the impeller.
How often should I replace the water pump impeller?
As a preventative maintenance best practice, impellers should be inspected annually and replaced every 1-2 years or every 200-300 hours of operation, whichever comes first. Refer to your generator's service manual for manufacturer-specific maintenance intervals.
Is this an OEM part?
This listing is an aftermarket replacement (not OEM). It was built to OEM-level specifications with comparable materials, manufactured in an ISO 9002 facility, and batch-inspected for quality and consistency.
What are the shipping speed and cost?
We ship worldwide quickly—typical transit time is 5–15 days. Standard shipping is free to most regions, and any available expedited options will appear at checkout.
What is the warranty and return policy?
This product is covered by a 1-year warranty against manufacturing defects under normal use. If you encounter an issue, please contact our support team with your order details. Returns are accepted within our standard return window for items that are unused and in their original condition.
Safety & Important Info
- Verify images and specifications against your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement part, not an OEM component. All mentions of brand names and part numbers are for reference purposes only.
- Professional installation is recommended for safety and performance. Improper installation can lead to engine damage.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world conditions.
- Fast Global Fulfillment — We offer free standard delivery to most regions with a typical transit time of 5–15 days.
- Manufacturer-Direct Value — By working directly with our manufacturing partners, we provide fair pricing without compromising on materials or quality control.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
