Water Pump Impeller – Fits Mercury/Mariner 25-50HP (Replaces 47-8M0024502, 47-850893)

Water Pump Impeller – Fits Mercury/Mariner 25-50HP (Replaces 47-8M0024502, 47-850893)

This water pump impeller is designed for a wide range of Mercury/Mariner outboards from 25HP to 50HP (both 2 & 4-Stroke engines, 1984-up) and Force/Chrysler outboards from 25HP to 75HP (2-Stroke engines, 1995-1999). It serves as a direct replacement for various water pump assemblies within these models.

It directly replaces Mercury Marine part numbers 47-850893, 47-85089, 47-8508910, 47-8508920, 47-8M0024502, 47-8M0027792, and 8M0204712, ensuring broad compatibility.

• Installation: Direct OEM-style replacement for a hassle-free fit.
• Material: Constructed from durable neoprene rubber for reliable performance.
• Includes: One 6-blade water pump impeller.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Mercury/Mariner Outboards

Force/Chrysler Outboards

Technical Specifications

Package Contents

• 1 x Water Pump Impeller (Replaces 47-850893 / 47-8M0024502)

Installation Guide

1. Disconnect Power: Disconnect the battery and spark plug wires to prevent accidental starting.
2. Access the Lower Unit: Drain the gear lube from the lower unit. Remove the bolts securing the lower unit (gearcase) to the midsection.
3. Remove the Lower Unit: Carefully lower the gearcase away from the engine. You may need to disconnect the shift shaft linkage.
4. Open the Water Pump Housing: Locate the water pump assembly on top of the gearcase. Remove the bolts securing the water pump cover.
5. Inspect and Remove Old Impeller: Lift off the housing cover. Note the rotational direction of the old impeller fins as you remove it. Pry out the old impeller from the housing.
6. Clean and Inspect: Thoroughly clean the inside of the pump housing and wear plate. Inspect them for deep grooves, scoring, or corrosion. Replace if significant wear is found.
7. Install New Impeller: Lightly lubricate the inside of the pump housing with a water-resistant grease or soapy water. Slide the new impeller down the driveshaft and into the housing, rotating the driveshaft in its normal direction of operation to bend the fins correctly.
8. Reassemble Pump Housing: Install new gaskets and re-seat the water pump cover. Torque the bolts to the manufacturer's specifications.
9. Reattach Lower Unit: Reconnect the shift linkage and carefully guide the lower unit back into place, ensuring the driveshaft, water tube, and shift shaft align properly.
10. Secure and Refill: Secure the lower unit with its bolts, torquing them to spec. Refill the gearcase with fresh gear lube.
11. Final Checks: Reconnect spark plug wires and the battery. Start the engine using a water supply (flushing muffs) and verify that water is exiting the "telltale" indicator, confirming the pump is working.

Troubleshooting & FAQ

Q: How do I confirm this impeller fits my specific engine?

A: First, check the Compatible Engine Models tables on this page. Cross-reference your engine's brand, model, HP, and year/serial number range. For added certainty, compare the dimensions and part numbers listed in our Technical Specifications and Part Number Cross-Reference sections to your old part.

Q: How often should a water pump impeller be replaced?

A: As a preventative maintenance item, most manufacturers recommend replacing the impeller every 1-2 years or every 100-200 hours of use, whichever comes first. This can vary based on operating conditions (e.g., saltwater vs. freshwater, sandy/silty water).

Q: What are common signs of a failing impeller?

A: A weak or intermittent water stream from the engine's tell-tale outlet is the most common sign. Other indicators include the engine overheating at idle or low speeds, or a high temperature warning alarm. A brittle or cracked impeller found during inspection also warrants immediate replacement.

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?

• 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.