Water Pump Impeller Kit – Fits Johnson F6B-9 Series Pumps
This water pump impeller kit is a direct replacement for Johnson F6B-9 series pumps, commonly found in Indmar Monsoon, Hammerhead, and Raptor engines (320HP–350HP). It is also compatible with select Volvo Penta and Yanmar marine engines that utilize the corresponding part numbers.
This kit provides a reliable solution for replacing worn or damaged impellers, a critical component for engine cooling. It is designed to meet or exceed OEM specifications for fit, form, and function.
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Complete Kit: Includes the neoprene impeller, a replacement O-ring, and a paper gasket for a full-service replacement.
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High-Quality Materials: Features a durable, 12-blade neoprene rubber impeller with a solid brass spline-drive insert for longevity and corrosion resistance.
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Direct Installation: Designed as a direct drop-in replacement for the original pump components, requiring no modifications.
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand |
Part Number |
| Johnson |
09-812B-1 / 09-812B |
| Indmar |
S685007 / 685001 |
| Sierra |
18-3306 |
| Yanmar |
119773-42600 |
| Jabsco |
13554-0001-P |
| Yamaha |
6TA-12457-00 |
Compatible Engine Models
Confirm your engine model/year in the table below.
| Brand |
Model |
Rated HP |
Stroke |
OEM Part No. |
Notes |
| Indmar |
Monsoon |
320HP |
4-Stroke |
S685007 |
Found in Supra, Moomba, Mastercraft & Tige boats |
| Indmar |
Monsoon |
325HP |
4-Stroke |
S685007 |
Found in Supra, Moomba, Mastercraft & Tige boats |
| Indmar |
Monsoon |
330HP |
4-Stroke |
S685007 |
Found in Supra, Moomba, Mastercraft & Tige boats |
| Indmar |
Monsoon |
335HP |
4-Stroke |
S685007 |
Found in Supra, Moomba, Mastercraft & Tige boats |
| Indmar |
Monsoon |
340HP |
4-Stroke |
S685007 |
Found in Supra, Moomba, Mastercraft & Tige boats |
| Indmar |
Monsoon |
350HP |
4-Stroke |
S685007 |
Found in Supra, Moomba, Mastercraft & Tige boats |
| Indmar |
Hammerhead |
|
4-Stroke |
S685007 |
|
| Indmar |
Raptor |
|
4-Stroke |
S685007 |
|
| Yanmar |
ME420TI |
|
4-Stroke |
119773-42600 |
|
Technical Specifications
| Specification |
Value |
| Product Type |
Water Pump Impeller Kit |
| Installation |
Direct replacement |
| Impeller Material |
Neoprene rubber with brass insert |
| Impeller Design |
12 blades with spline drive |
| Impeller Dimensions |
2-1/4" OD × 1-15/16" width (57.15 mm × 49.21 mm) |
| Shaft Type |
5/8" spline drive brass insert |
| Compatible Pumps |
Johnson F6B-9, 10-24232-1, 10-24915-01, Jabsco 50410-1201 |
Package Contents
- 1 x Impeller (Neoprene + Brass) 12 Blades OD 2-1/4" x 1-15/16" Wide Spline Drive
- 1 x O-Ring
- 1 x Gasket
Installation Guide
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Safety First: Ensure the engine is off and cool. Close the raw water intake seacock to prevent water from entering the boat.
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Access the Pump: Locate the raw water pump. You may need to remove a cover or other components to access it easily.
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Remove the Cover Plate: Unscrew the bolts holding the pump's cover plate in place. Keep the screws in a safe place.
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Remove the Old Impeller: Note the direction the impeller blades are bent. Use impeller pullers or two screwdrivers to carefully pry out the old impeller from the pump housing.
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Clean and Inspect: Clean any debris or old gasket material from the pump housing and cover plate. Inspect the housing for scoring or damage.
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Install New Gasket/O-Ring: Place the new gasket or O-ring included in the kit into the groove on the pump body.
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Install the New Impeller: Lightly lubricate the inside of the pump housing and the new impeller with a water-based lubricant or dish soap. Insert the new impeller, bending the blades in the same direction as the old one was installed.
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Reassemble and Test: Reattach the cover plate and tighten the screws evenly. Open the seacock, start the engine, and immediately check for proper water flow from the exhaust and inspect the pump for any leaks.
Troubleshooting & FAQ
Q: How do I know if this impeller fits my Indmar engine?
A: This kit is designed for Indmar Monsoon, Hammerhead, and Raptor engines that use a Johnson F6B-9 series pump. The surest way to confirm fitment is to verify your pump model or match your existing part number to one of the cross-references, such as Indmar S685007 or Johnson 09-812B-1.
Q: What are the signs my impeller is failing?
A: The most common sign is a rise in engine temperature or an overheating alarm. Other indicators include a noticeable reduction in water flow from the exhaust, visible cracks or missing chunks on the impeller blades, or a stiff, inflexible rubber consistency during inspection.
Q: How often should I replace my water pump impeller?
A: For preventative maintenance, we recommend inspecting your impeller annually and replacing it every 1 to 2 boating seasons, depending on usage. If you frequently operate in water with high levels of sand or silt, 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, especially the dimensions and shaft type, 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. Brand names and part numbers are used for reference purposes only.
- Professional installation is recommended to ensure safety and optimal performance. Improper installation can lead to engine damage.
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.