8M0151470 Maintenance Kit for Mercury Mariner 15HP 20HP EFI 4-Stroke | JLM Marine

8M0151470 Maintenance Kit for Mercury Mariner 15HP 20HP EFI 4-Stroke

This comprehensive maintenance kit is specifically designed for Mercury Mariner 15HP and 20HP EFI 4-Stroke outboard motors with serial numbers 0R833820 and above. It provides all the essential components needed for a complete service, including water pump impeller assembly, thermostat, fuel filter, oil filter, and critical gaskets.

Direct Replacement for OEM Part Number: 8M0151470, 8M0135821. This aftermarket kit delivers reliable performance and fit for your scheduled maintenance needs.

• Complete maintenance solution with water pump, filters, and sealing components
• Designed for EFI (Electronic Fuel Injection) 4-stroke models
• Includes all necessary gaskets and seals for proper installation

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

This complete maintenance kit includes the following components:

• 1 × Water Pump Impeller Kit (46-8M0135821 / 8M01358211) containing:
  • 8M0134493 Housing base
  • 8M0137347 Key
  • 8M0135804 Gasket
  • 8M0135806 Gasket
  • 8M0135805 Plate
  • 803751 Insert cup
  • 8036674 Seal
  • 8M0134492 Housing
  • 803752 Oil seal
  • 8M0135803 Impeller
• 1 × Thermostat (8M0139434)
• 1 × Thermostat Gasket (27-8M0214960)
• 1 × Fuel Filter (35-8M0134466)
• 1 × Oil Filter (35-8M0162831)
• 1 × Cotter Pin (8150264)
• 3 × Drain Gaskets (1 × 12-895146 & 2 × 8M0082880)

Installation Guide

1. Preparation: Disconnect the battery and gather necessary tools including a torque wrench, screwdrivers, and basin for draining fluids. Ensure your work area is clean and well-lit.
2. Oil Change: Remove the oil drain plug using the appropriate drain gasket from the kit and drain old oil completely. Replace the oil filter (35-8M0162831) and refill with manufacturer-recommended oil to proper level.
3. Fuel Filter Replacement: Locate the fuel filter assembly and relieve fuel system pressure. Replace the old fuel filter with the new unit (35-8M0134466) ensuring proper orientation and secure connections.
4. Water Pump Disassembly: Remove the lower unit and gearcase to access the water pump housing. Carefully remove the old impeller, housing, and all gaskets.
5. Inspect Components: Clean the water pump housing base and inspect for wear, corrosion, or damage. Replace the housing if any damage is found.
6. Install New Impeller: Lubricate the new impeller (8M0135803) with glycerin or soapy water and install with blades oriented in the correct rotation direction. Insert the key (8M0137347) into its slot.
7. Assemble Water Pump: Install the insert cup (803751), plate (8M0135805), seals (8036674, 803752), and gaskets (8M0135804, 8M0135806) in proper sequence. Place the housing (8M0134492) and housing base (8M0134493) ensuring proper alignment.
8. Thermostat Replacement: Remove the thermostat cover and old thermostat. Install the new thermostat (8M0139434) with the new gasket (27-8M0214960) ensuring proper seating and orientation.
9. Reassemble Lower Unit: Reinstall the gearcase and lower unit, torquing all fasteners to manufacturer specifications. Install the cotter pin (8150264) where required.
10. Final Checks: Verify all drain plugs are tight with new gaskets installed. Double-check all connections, fasteners, and hose clamps.
11. System Test: Reconnect the battery and run the engine in a test tank or on muffs. Check for proper water flow from the telltale, leaks, and smooth operation.
12. Post-Installation: Monitor engine temperature and performance during initial use. Inspect for leaks after the first run and re-torque fasteners as needed.

Troubleshooting & FAQ

Q: How do I confirm this maintenance kit fits my Mercury outboard?
A: Verify your engine is a Mercury Mariner 15HP or 20HP EFI 4-Stroke model with serial number 0R833820 or above. Check your engine's identification plate or consult the Mercury serial number guide linked above to confirm compatibility before ordering.

Q: How often should I replace the water pump impeller and perform this maintenance?
A: Mercury recommends replacing the water pump impeller annually or every 100-300 hours of operation, whichever comes first. Oil and fuel filters should be changed at least once per season or per manufacturer's maintenance schedule to ensure optimal engine performance and longevity.

Q: What are the signs that my water pump or thermostat needs replacement?
A: Common warning signs include weak or no water stream from the telltale outlet, engine overheating, steam from the engine, loss of power, or the overheat alarm activating. If you notice any of these symptoms, inspect and replace the water pump impeller and thermostat immediately.

Q: Can I replace just the impeller or do I need the complete water pump kit?
A: While you can replace just the impeller, it's highly recommended to replace all gaskets, seals, and wear components together as included in this complete kit. This ensures proper sealing, prevents future leaks, and maximizes the service life of your repair.

Q: Do I need any special tools to install this maintenance kit?
A: Basic marine mechanic tools are required including socket sets, screwdrivers, a torque wrench, and a lower unit removal tool. You'll also need impeller grease or glycerin for lubricating the new impeller during installation. Consult your Mercury service manual for specific torque specifications.

Q: Is this an OEM or aftermarket part? What's the difference?
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.