Water Pump Impeller Kit – Fits Onan 4.0, 6.0, 6.5, 7.5 KW Generators
This water pump impeller kit is designed for Onan marine generators in the 4.0–7.5 KW power range, specifically the MCCK and MDJE series. It is engineered for a direct fit in models equipped with a 4-screw cover pump.
This kit serves as a direct replacement for several Onan, Globe, BCO, and GCS part numbers, ensuring broad compatibility for the specified generator models.
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Kit Contents: Includes one 6-blade CR neoprene impeller with a brass insert and one matching 4-hole gasket.
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Installation: Designed for a direct OEM replacement fit, simplifying maintenance.
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Material: The impeller is made from durable CR neoprene, suitable for marine environments.
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| 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 |
Compatible Engine Models
Confirm your engine model/year in the table below.
| 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 Specifications
| Specification |
Value |
| 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) |
Package Contents
- 1 x Water Pump Impeller (Replaces 131-0386)
- 1 x Gasket (Replaces 131-0210)
Installation Guide
- Shut down the generator and close the raw water seacock.
- Place a collection pan under the water pump to catch any spilled coolant or water.
- Remove the four screws from the water pump cover plate.
- Carefully pry off the cover plate. The old impeller may come out with it.
- Remove the old impeller and gasket. Clean any debris or old gasket material from the pump housing and cover plate.
- Lightly lubricate the inside of the pump housing and the new impeller with a water-based marine lubricant.
- Insert the new impeller into the housing, bending the blades in the direction of the pump's rotation.
- Position the new gasket on the pump housing.
- Re-install the cover plate and tighten the screws in a star pattern to ensure an even seal. Do not overtighten.
- Open the seacock, start the generator, and immediately check for any water leaks and verify proper water flow from the exhaust.
Troubleshooting & FAQ
Q: How do I know if this impeller fits my Onan generator?
A: This kit fits Onan MCCK and MDJE series generators (4.0–7.5 KW) equipped with a 4-screw cover pump. To guarantee fitment, please verify your existing part number against those listed in our cross-reference table, such as 131-0386 or 131-0257.
Q: What are common signs that my impeller needs to be replaced?
A: Key indicators of a failing impeller include the generator overheating, a noticeable reduction in water flow from the exhaust outlet, visible cracks or missing blades on the impeller itself, and a brittle or stiff feel to the rubber.
Q: How often should I replace my generator's water pump impeller?
A: For preventative maintenance, we recommend inspecting the impeller annually and replacing it every one to two years, depending on usage hours and water conditions (e.g., saltwater vs. freshwater). Proactive replacement helps prevent unexpected engine overheating.
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?
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Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
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Fast Global Shipping: Free delivery worldwide in 5–15 days.
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Direct from Manufacturer: Competitive pricing without compromising quality.