Water Pump Impeller Kit – Fits Mercury/Mariner 200-250 HP (Replaces 817275A5)

Water Pump Impeller Kit – Fits Mercury/Mariner 200-250 HP (Replaces 817275A5)

This water pump impeller rebuild kit is designed for Mercury/Mariner 200-250 HP EFI, DFI, Carb, Pro XS, and 4-Stroke outboard engines. It provides all necessary components for a complete overhaul of the lower unit water pump assembly.

This kit serves as a direct replacement for multiple OEM and aftermarket part numbers, ensuring broad compatibility for various 3.0L engine models.

• Installation Method: Direct OEM-style replacement.
• Primary Components: Includes impeller, housing, gaskets, and seals for a full service.
• Application: Specifically designed for the lower unit water pump assembly.

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.

Technical Specifications

Package Contents

• 1 x Water Pump Rebuild Kit (Replaces 817275A5)
• 1 x Seal Kit-OBM (Replaces 816575A2)
• 1 x Upper Water Pump Gasket (Replaces 8172771)
• 1 x Aluminum Cover Gasket (Replaces 430331)

Installation Guide

1. Safety First: Disconnect the battery and ensure the outboard is in the neutral position.
2. Lower Unit Removal: Remove the bolts securing the lower unit (gearcase) to the engine's upper casing.
3. Detach Gearcase: Carefully lower and separate the gearcase from the upper unit. Be mindful of the shift shaft, which may need to be disconnected.
4. Access Water Pump: Locate the water pump housing on top of the gearcase. Remove the mounting bolts to lift it off the driveshaft.
5. Disassemble Old Pump: Take off the old housing. Remove the impeller, woodruff key, wear plate, and old gaskets. Note the rotational direction of the old impeller's vanes.
6. Clean Surfaces: Thoroughly clean all mating surfaces, removing any old gasket material or sealant residue.
7. Install New Components: Place the new gaskets and wear plate onto the gearcase. Install the new woodruff key into the driveshaft.
8. Install New Impeller: Slide the new impeller onto the driveshaft, turning the shaft clockwise to help bend the vanes into the correct orientation.
9. Install New Housing: Lightly lubricate the interior of the new pump housing with marine grease or soapy water, then press it down over the impeller with a slight twisting motion.
10. Secure Housing: Align the bolt holes and tighten the housing bolts to the manufacturer-specified torque.
11. Reassemble: Reattach the gearcase to the upper unit, making sure the driveshaft, shift shaft, and water tube are properly aligned.
12. Final Test: Once fully assembled, start the engine using a flush-out device ("earmuffs") or in the water to confirm water is pumping correctly from the tell-tale outlet.

Troubleshooting & FAQ

Q: How do I confirm this kit fits my engine?
A: The most reliable method is to match your engine's model and serial number against the compatibility chart. Additionally, cross-reference your existing part number with the numbers listed in our cross-reference table. If you are unsure, please contact us with your engine details before purchasing.

Q: What are the signs of a failing water pump impeller?
A: Common symptoms include a weak or non-existent water stream from the "tell-tale" outlet, engine overheating alarms, and reduced engine performance. A visual inspection may reveal cracked, brittle, or broken vanes on the old impeller.

Q: How often should the water pump impeller be replaced?
A: For preventative maintenance, it is recommended to inspect and/or replace the water pump impeller every 100 operating hours or at least once a year, whichever comes first. This is especially important for boats used in saltwater or sandy/silty conditions.

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.