Product Overview
Reliable custom rubber parts for industrial applications
Quick Answer
The Johnson 09-821B rubber impeller is a flexible vane pump component for replacement, maintenance service and compatible fluid handling applications. Dimensions, blade profile, hub structure, shaft connection, rubber compound, Shore A hardness, tolerance and packaging must be confirmed by drawing, official specification or physical sample before production.
The Johnson 09-821B rubber impeller is a flexible vane pump component used as a replacement reference for compatible pump systems. This page does not assume unconfirmed dimensions, blade quantity, material grade, hardness, color or insert details. Outer diameter, height, hub structure, shaft connection, blade profile and rubber compound should be confirmed by drawing, official specification or physical sample.
Product Overview
The Johnson 09-821B Rubber Impeller is a 12-blade flexible Neoprene impeller manufactured as a direct-fit replacement for Johnson Pump F75B series engine cooling pumps used across a wide range of Volvo Penta and Yanmar marine diesel engines. This part number has also been produced under the updated designation 09-821BT-1, and both are fully cross-referenced and interchangeable in the aftermarket supply chain. It is widely specified for engine cooling, water transfer, wash down, and bilge pumping duties, making it one of the standard reference impellers used across recreational and commercial marine diesel engine cooling systems.
Key Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 09-821B (also listed as 09-821BT-1, 08-821B) |
| Material | Neoprene rubber |
| Number of Blades | 12 blades |
| Impeller Diameter | 65–65.8 mm (2.56″) |
| Impeller Width/Depth | 80 mm (3-1/8″ / 3.15″) |
| Shaft Hub Diameter | 25–25.4 mm (0.99″–1″) |
| Hub Insert Type | Brass Spline Drive (12-spline) |
| Approx. Weight | 0.95 lbs (~0.43 kg) |
| Kit Contents (7376-01K equivalent) | Impeller, multiple O-rings, lubricant/glycerine |
What Is the Johnson 09-821B Impeller?
The Johnson 09-821B is a flexible Neoprene rubber impeller with 12 curved blades mounted on a brass spline-drive hub, designed for use in Johnson Pump F75B series bronze flexible impeller pumps that circulate raw seawater or freshwater for marine diesel engine cooling. As the pump shaft rotates, the flexible Neoprene blades deform and re-expand within the pump housing to draw in and discharge cooling water — a self-priming action characteristic of flexible impeller pump design. This impeller is suitable for general water-pumping duties beyond engine cooling, including water transfer, washdown, and bilge water pumping.
Cross-Reference & Compatibility
| Brand | Part Number |
|---|---|
| Johnson | 09-821B, 08-821B, 09-821BT-1 |
| Volvo Penta | 21422649, 876771, 21951358, 22994993, 3887761, 22000061, 24139373, 3825113, 3836563 |
| Yanmar | 119574-42550, 119574-42552, 119578-42550, 119578-42501, 119578-42551 |
| MAN | 51.06500-7023, 51.06500-7034 |
| Mallory | 9-45714 |
| CEF (aftermarket) | 500162 |
| Sierra (aftermarket) | 18-45714 |
| JMP Marine (aftermarket) | 7376-01, 7376-01K, 7376K (kit) |
Compatible Johnson Pump models: F75B-9 (10-13141-01, 10-13141-02, 10-13142-01, 10-13142-02, 10-13153-01, 10-13170-01, 10-13265-01, 10-13286-01, 10-13306-01, 10-24413-01, 10-24413-02).
Engine applications: Volvo Penta D6 series, TAMD63L-A, TAMD63P-A; Yanmar 6LY2, 6LY3 (1997 onwards); MAN D2866LE/401 and D2866LE/401/402; Bayliner/Hino Motors W06D-T1-11 310/3000.
Why Neoprene Is Used for This Impeller
- Wide chemical resistance — Neoprene tolerates exposure to fresh water and salt water typical of raw-water engine cooling, transfer, washdown, and bilge pumping duties
- Industry-standard flexibility — Neoprene remains the benchmark material for Johnson Pump’s F75B series flexible impeller family
- High blade count for flow volume — the 12-blade configuration provides strong displacement per rotation, suited to mid-size marine diesel engine cooling demands
- Reliable spline engagement — the molded-in brass 12-spline drive insert ensures secure, slip-free torque transfer from the pump shaft
- Alternative compound available — a Nitrile version is also produced for oil-resistant applications where oil contamination is a concern, alongside a specialized MC97 rubber compound offered by the original manufacturer for optimized cold-start cooling performance
Installation & Maintenance Notes
- Dry-running caution — like all flexible impeller pumps, this impeller must never be run dry, even briefly, as the Neoprene blades can overheat and deform without water lubrication and cooling
- Recommended replacement interval — typically every 1–2 boating seasons or per engine manufacturer service schedule, to prevent unexpected cooling failure
- Service kit availability — commonly supplied as a complete kit including multiple O-rings and lubricant/glycerine for a full service replacement in one part number
- Installation orientation — blade curvature must be installed in the correct rotational direction per the pump housing orientation to ensure proper self-priming function
Applications
- Volvo Penta D6 series, TAMD63L-A, TAMD63P-A marine diesel engine cooling pumps
- Yanmar 6LY2, 6LY3 marine diesel engine cooling pumps
- MAN D2866LE marine diesel engine cooling circuits
- General water transfer, washdown, and bilge pumping duties
- Johnson Pump F75B series bronze flexible impeller pump bodies
Custom & OEM Manufacturing Capability
- Material options — Neoprene, NBR (Nitrile), NR, EPDM, Silicone, HNBR, SBR
- Hardness range — 30–95 Shore A
- Temperature range — -40°C to +300°C depending on compound selection
- Dimensional tolerance — ±0.05 mm
- Hub options — brass spline drive, key drive, double flat drive, or custom insert configuration
- Certification — ISO 9001 compliant manufacturing available
- Custom branding — OEM and ODM orders accepted with customer logo and packaging
Why Source from Julong Rubber?
- Full cross-reference matching engineered to Johnson, Volvo Penta, Yanmar, and MAN dimensional equivalents
- ISO 9001 certified manufacturing and inspection
- Full elastomer range — Neoprene as standard, plus NBR, NR, EPDM, Silicone alternatives
- Precision brass spline hub molding — secure torque transfer, no slip
- Low MOQ with tiered volume pricing
- Fast delivery for stock cross-reference parts
- OEM/ODM capability — custom logo, packaging, and specification accepted
- Marine diesel engine application experience across commercial and recreational vessels
FAQ
Can this impeller be supplied as a Johnson 09-821B replacement?
Yes, the product can be reviewed as a replacement reference for Johnson 09-821B applications. However, the part number alone is not enough for production approval. Dimensions, blade profile, shaft connection, rubber compound and pump compatibility must be confirmed before manufacturing.
Why are exact dimensions not listed on this page?
Exact dimensions are not listed because no confirmed drawing, official specification or measured sample data has been provided. For rubber impellers, unsupported dimensions can cause installation problems, reduced flow, excessive friction or early blade damage. Confirmed data is required before production.
Can the impeller be manufactured from an old sample?
Yes. A physical sample can be used for reverse engineering when the original drawing is unavailable. The sample should be checked for wear, deformation and blade damage. Critical dimensions, pump chamber clearance and operating conditions should still be confirmed before tooling.
How should buyers select the rubber material?
Rubber material selection depends on the working liquid, temperature, rotation speed, dry-running risk, oil exposure and chemical contact. Buyers should provide the exact media and service conditions. Material selection depends on the application conditions.
Is tooling required for this rubber impeller?
Tooling is usually required for molded rubber impellers with custom blade geometry, hub structure or insert design. Tooling cost depends on the drawing and product structure. Prototype samples can be reviewed before batch production.
Are samples available before bulk production?
Samples are available upon request. Sample preparation depends on the confirmed dimensions, rubber compound, Shore A hardness, insert structure, tooling status and inspection requirements. Please provide a drawing, official specification or physical sample for review.
Request a Custom Quote
Send your Johnson 09-821B rubber impeller drawing, official specification, pump model or physical sample for review. Please include dimensions, shaft connection, blade profile, rubber material, hardness, working liquid, temperature, speed, rotation direction, quantity and packaging requirements.
