8M0251130 Annual Service Kit for Mercury Mariner OptiMax DFI 1.5L | JLM Marine

8M0251130 Annual Service Kit for Mercury Mariner OptiMax DFI 1.5L

This comprehensive annual service kit is engineered specifically for Mercury Mariner OptiMax 75-115 HP DFI 1.5L engines from 1999 to 2016. It provides all the essential maintenance components needed to keep your outboard running at peak performance, including the water pump impeller, seals, gaskets, thermostat, fuel filter, and gear oil pump.

Direct replacement for OEM part number 8M0251130, this kit simplifies your annual maintenance routine by bundling critical service parts in one package.

• Complete maintenance solution with 17 components covering water pump, fuel system, and lubrication
• Designed for Mercury Mariner OptiMax Direct Fuel Injection (DFI) 1.5L engines
• Includes premium impeller, thermostat, fuel filter, and all necessary seals and gaskets

Part Number Cross-Reference

Use this table to confirm the OEM part number for your engine:

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 annual service kit includes 17 genuine replacement components for comprehensive maintenance:

• Water Pump Components:
  • 47-43026Q02 Impeller × 1
  • 26-8M2014338 Seal × 1
  • Seal × 1
  • 8172761 Plate × 1
  • 25-21836 O-ring × 2
  • 27-8M0142616 Gasket × 1
  • 27-8172771 Gasket × 1
  • 28-8M0032833 Key × 1
• Seals & Gaskets:
  • 26-45577 Seal × 1
  • 25-90196 O-ring × 1
  • 26-830749 Gasket × 3
  • 8M007119 Drain Gasket × 1
  • 830749 Drain Gasket × 3
• Cooling System:
  • 833072003 Thermostat × 1
• Fuel System:
  • 35-8M0060041 Fuel Filter × 1
• Lubrication System:
  • 24OP149 Gear Oil Pump × 1

Installation Guide

1. Preparation: Disconnect the spark plug wires and ensure the engine is cool. Gather necessary tools including screwdrivers, wrenches, and a torque wrench.
2. Water Pump Service: Remove the lower unit from the engine following your service manual. Separate the water pump housing and remove the old impeller, plate, and seals.
3. Install New Impeller: Lubricate the new impeller (47-43026Q02) with glycerin or soapy water and install it into the housing with blades oriented correctly. Insert the drive key (28-8M0032833) into the driveshaft slot.
4. Replace Seals & Gaskets: Install the new plate (8172761), all seals (26-8M2014338, 2210, 26-45577), O-rings (25-21836, 25-90196), and gaskets (27-8M0142616, 27-8172771, 26-830749). Ensure all mating surfaces are clean and dry.
5. Reassemble Water Pump: Torque the water pump housing bolts to manufacturer specifications. Verify that the impeller rotates freely without binding.
6. Thermostat Replacement: Locate the thermostat housing on the cylinder head and remove the cover. Replace the old thermostat with the new unit (833072003) ensuring correct orientation.
7. Fuel Filter Change: Locate the fuel filter assembly on the engine. Replace the old filter element with the new fuel filter (35-8M0060041) and inspect all fuel lines for cracks or deterioration.
8. Gear Oil Service: Install the new gear oil pump (24OP149) if replacing the old unit. Drain old gear oil from the lower unit using the drain gaskets provided (8M007119, 830749).
9. Refill Gear Oil: Refill the lower unit with fresh Mercury Premium or High-Performance gear oil to the proper level. Install new drain gaskets and torque plugs to specification.
10. Reinstall Lower Unit: Apply water-resistant grease to the driveshaft splines and reinstall the lower unit. Torque all mounting bolts per service manual specifications.
11. Final Inspection: Double-check all fasteners, connections, and gasket seals. Reconnect spark plug wires and verify all components are properly secured.
12. Test Run: Start the engine with water supply connected (flush muffs or in-water) and check for proper water flow from the telltale. Inspect for any leaks and verify smooth operation.

Troubleshooting & FAQ

How do I confirm this kit fits my Mercury OptiMax engine?
Verify your engine is a Mercury Mariner OptiMax DFI 1.5L model rated between 75-115 HP and manufactured between 1999-2016. Check your engine's serial number plate or consult your owner's manual to confirm the model designation and year.

How often should I perform this annual service?
Mercury recommends performing this complete service annually or every 100 hours of operation, whichever comes first. If you operate in saltwater, sandy conditions, or commercially, consider servicing more frequently (every 50-75 hours).

What are the signs that my water pump impeller needs replacement?
Watch for reduced water flow from the telltale (indicator stream), engine overheating, steam from the powerhead, or poor performance. If the impeller is more than one year old, replace it preventively even if symptoms aren't present.

Can I reuse the old gaskets and seals when installing new components?
No, always replace all gaskets, seals, and O-rings during service even if they appear intact. Old gaskets compress and lose sealing ability, which can lead to leaks, air intrusion, or contamination.

Do I need special tools to complete this service?
Basic hand tools are sufficient for most tasks: socket set, screwdrivers, and pliers. A torque wrench is highly recommended for proper fastener tension, and a gear oil pump makes lower unit servicing cleaner and easier.

What's the difference between this aftermarket kit and the OEM version?
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.

How fast do you ship and how much does it cost?
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.

What is your warranty and return policy?
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.