Water Pump Impeller Maintenance Kit – Fits Mercury/Mariner/Tohatsu 4/5/6 HP 4-Stroke (Replaces 8M0120836, 3GR-87500-0)

Water Pump Impeller Maintenance Kit – Fits Mercury/Mariner/Tohatsu 4/5/6 HP 4-Stroke

This water pump impeller maintenance kit is designed for Mercury/Mariner 4-6 HP 4-Stroke outboard engines (serial numbers 0R411838 and above) and compatible Tohatsu 4-6 HP 4-Stroke models. It contains essential components for cooling system service to maintain engine performance and prevent overheating.

This kit is a direct replacement for Mercury part number 8M0120836 and Tohatsu part number 3GR-87500-0.

• Installation Type: Direct replacement
• Fuel Compatibility: Gasoline
• Primary Function: For cooling system maintenance and general service

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.

Confirm your engine model/year in the table below.

Mercury/Mariner

Tohatsu

Technical Specifications

Package Contents

• 1 x Water Pump Impeller (47-16154-3)
• 1 x Cotter Pin (8150264)
• 1 x Pin Key (28-16155)
• 1 x Thermostat (804540)
• 1 x Thermostat Gasket (27-8M0214960)
• 1 x O-Ring (25-16131)
• 1 x Oil Seal (26-16130)
• 1 x Fuel Filter (35-8M0157133)
• 1 x Gaskets (8035161)
• 2 x Drain Gasket (27-95220)

Installation Guide

1. Disconnect the engine's battery and remove the spark plug wire(s) to prevent accidental starting.
2. Access the lower unit by disconnecting any shift linkage and removing the bolts securing the lower unit to the midsection.
3. Remove the lower unit carefully from the outboard's main housing.
4. Locate and open the water pump housing on top of the gearcase by removing the retaining bolts.
5. Remove the old impeller and associated components, noting their orientation.
6. Clean the pump housing thoroughly before installing new components.
7. Install the new impeller with a slight twisting motion in the correct rotational direction.
8. Reassemble the pump housing with new gaskets and seals from the kit.
9. Reattach the lower unit, aligning the driveshaft and water tube properly.
10. Reconnect the battery and test the engine with water supply to confirm proper cooling system function.

Troubleshooting & FAQ

Q: How do I confirm this fits my Mercury/Mariner engine?

A: This kit fits Mercury and Mariner 4, 5, and 6 HP EFI 4-stroke outboards from 2015 and newer with a serial number of 0R411838 and above. Please verify your serial number before ordering.

Q: How do I know if my Tohatsu engine is compatible?

A: This kit is compatible with Tohatsu MFS4, MFS5, and MFS6 4-stroke models that use the OEM part number 3GR-87500-0. We recommend checking your engine's service manual or original parts to confirm.

Q: How often should I perform this service?

A: This kit is designed for comprehensive cooling system maintenance. For Mercury engines, it aligns with components needed for the 300-hour service interval. Refer to your engine's service manual for specific maintenance schedules.

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.