Flexible Rubber Water Pump Impeller 21414-0001 – 6 Blade Neoprene D-Bore – Fits Yanmar 128170-42070

How to Match This Part

This is a flexible rubber raw water pump impeller. It sits inside the pump housing behind the cover plate and is driven by a single-flat (D-bore) shaft. It replaces the primary original part number Jabsco 21414-0001 (also 1414-0001), and is also supplied against JMP 6000-01 / 6000 and Yanmar 128170-42070.

Match this part by checking your engine in this order:
1. Original impeller part number (stamped on the old impeller or listed in the pump section of your parts catalog)
2. Blade count (this listing is 6 blades)
3. Drive type (this listing is a single-flat / D-bore hub, 8 mm)
4. Diameter and width (this listing is 32 mm diameter and 12 mm wide, not the 51 mm 6303-0001 family)

Identify it physically before ordering. This impeller has six vanes moulded in black neoprene around a machined brass D-bore insert. JMP 6000-01 is 32 mm diameter, 12 mm width and 8 mm bore. Excel also lists nitrile 0003 numbers for the same envelope; this listing is the neoprene cooling impeller shown in the product photos.

• ✓ Primary OEM: Jabsco 21414-0001
• ✓ Product form: 6-blade neoprene impeller, brass single-flat insert, 32 × 12 × 8 mm
• ✓ Fitment: part number, then size, then neoprene vs nitrile

Part Number Cross-Reference

Use this table to confirm equivalent part numbers. Nitrile 0003 numbers share the envelope but are a different compound. This listing is the neoprene impeller.

Compatible Engine Models

Confirm the original impeller number and count six blades on an 8 mm single-flat hub 12 mm wide. Do not assume every Yanmar 1GM-family pump uses this impeller.

Technical Specifications

Package Contents

This listing is for the impeller only, as shown in the impeller in the product images. Please refer to the part number cross-reference table to confirm component details.

Cover gasket, O-ring and lubricant are not included.

Installation Guide

1. 1 Stop the engine, let it cool, and close the raw water seacock so water cannot enter the boat while the pump is open.
2. 2 Remove the cover plate screws and lift off the cover. Keep the screws and the old gasket together so you can compare the seal size when reassembling.
3. 3 Note the D-bore orientation, then grip the brass insert and pull the old impeller straight off. Recover any broken vane pieces from the downstream cooling circuit before continuing.
4. 4 Clean the housing bore and the wear plate, and inspect them for scoring. Apply a marine-grade impeller lubricant, glycerine or soapy water to the bore and the new vanes. Do not use petroleum-based grease, which attacks neoprene.
5. 5 Align the single flat in the brass insert with the pump shaft, then press the impeller in while turning the shaft in the normal direction of rotation so all six vanes lay over the same way.
6. 6 Refit the cover plate with a serviceable gasket, tighten the screws evenly in a crisscross pattern, open the seacock, then start the engine and confirm a solid stream of cooling water and no leaks at the cover.

Note: Professional installation is recommended to ensure safety and optimal performance.

Troubleshooting & FAQ

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.
• The impeller is supplied on its own. Cover seals and lubricant must be ordered separately if your service procedure requires them.
• This is a 6-blade, 32 mm single-flat impeller, 12 mm wide with an 8 mm bore. It will not fit 51 mm 6303-0001 of the same drive type.
• Never run the pump dry. Even a few seconds without water will damage the neoprene vanes.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.