Yamaha 115 4 Stroke Fuel Pump Replacement: A Complete Guide for Boat Owners

If your Yamaha 115 4-stroke outboard is struggling to start, sputtering at high speeds, or losing power, a failing fuel pump is often the culprit. Replacing the fuel pump is a straightforward repair that can save you from costly breakdowns on the water. Most 2000-2012 Yamaha 115 4-stroke models use a fuel pump assembly that replaces OEM part numbers 68V-13907-04-00, 68V-13907-03-00, and 68V-13907-02-00. The cost for a replacement pump ranges from $79 to $310 depending on the brand and whether you choose an OEM or aftermarket part. For most owners, the smartest choice is a high-quality aftermarket pump like KEMSO, which offers better performance, a lifetime warranty, and significant savings compared to dealership parts.

Common Symptoms of a Failing Fuel Pump

Recognizing the early warning signs of fuel pump failure can prevent you from being stranded on the water. Here are the most common symptoms:

  • Hard starting or no-start: The engine cranks but won't fire up, or it takes multiple attempts to start. This is often the first sign of fuel delivery problems.
  • Sputtering or hesitation at high RPM: The engine runs fine at idle but stumbles or loses power when you try to accelerate.
  • Loss of power under load: The boat feels sluggish, especially when trying to get on plane or pulling a skier.
  • Fuel pressure fluctuations: You may notice the engine surging or running unevenly as the pump fails to maintain consistent pressure.
  • Whining noise from the fuel tank area: A healthy pump runs quietly. A loud whine indicates internal wear and impending failure.
  • Check engine light: Modern Yamaha outboards will often trigger the check engine light if fuel pressure is irregular.

Can you run with a bad fuel pump? No. It is not safe. A failing pump can cause the engine to stall without warning, which is dangerous in traffic or when navigating channels. Continuing to run can also damage other components like the fuel injectors or catalytic converter.

Tools and Parts Needed for Replacement

Before starting the job, gather the following items:

  • Replacement fuel pump (choose the correct one for your model year)
  • New gaskets and O-rings (most kits include these)
  • Fuel filter (replace at the same time for best results)
  • Basic hand tools: screwdrivers, socket set, pliers, and a torque wrench
  • Safety gear: safety glasses, gloves, and a fire extinguisher rated for flammable liquids
  • Shop towels and a drain pan for any fuel that spills
  • Zip ties for securing wires and hoses

Step-by-Step Installation Guide

1. Safety First

Disconnect the negative battery terminal. Work in a well-ventilated area away from any open flames or sparks. Have a fire extinguisher within reach. Never smoke near the work area.

2. Relieve Fuel System Pressure

Locate the fuel pressure relief valve on the engine. Carefully depress the valve to release pressure. This prevents fuel spray when you disconnect lines.

3. Access the Fuel Pump

The fuel pump is located inside the fuel tank. You will need to:

  • Remove the engine cowling
  • Disconnect the fuel lines and electrical connector
  • Remove the retaining ring or bolts securing the pump assembly
  • Carefully lift the pump assembly out of the tank

4. Install the New Pump

  • Remove the old pump from the assembly bracket
  • Replace all rubber seals and O-rings with new ones (never reuse old seals)
  • Install the new fuel pump, ensuring it is properly seated
  • Attach the new fuel strainer
  • Reassemble the pump assembly into the tank

5. Reconnect and Test

  • Reconnect fuel lines and electrical connector
  • Reinstall the retaining ring
  • Reconnect the battery
  • Turn the ignition to the "ON" position (do not start) to allow the pump to prime
  • Check for any fuel leaks carefully
  • Start the engine and verify proper operation

Why Choose KEMSO for Your Yamaha 115 Fuel Pump

When it's time to replace your fuel pump, the brand you choose makes a significant difference in performance and long-term reliability. KEMSO fuel pumps are designed as high-performance, direct OEM replacements for a wide range of applications, including Yamaha outboards.

Here’s what sets KEMSO apart:

  • High Performance & OEM Replacement: KEMSO pumps are engineered to be direct replacements for your original equipment. They deliver over 20% more flow at 43 psi compared to stock pumps, providing better throttle response and overall engine performance.
  • Unmatched Quality: KEMSO has a rigorous quality control program (ISO/TSO), and each pump is individually tested for flow and performance. This attention to detail means you can install a KEMSO pump with confidence.
  • Complete Kit: Most KEMSO fuel pump kits come with everything you need for a successful installation: the pump, multiple gradient density fuel strainers, tank seals, flex hose, O-rings, wiring connectors, and hose clamps.
  • Ethanol Compatible: KEMSO pumps are designed for use with both gasoline and E85/ethanol, making them a versatile option for different fuel blends.
  • Lifetime Warranty: Every KEMSO fuel pump comes with a lifetime warranty, backed by a serialized body for tracking. This gives you complete peace of mind knowing your investment is protected for as long as you own your boat.
  • USA-Based Support: KEMSO offers technical support from USA-based technicians, making it easy to get help if you have questions during installation or operation.

Cost Comparison: KEMSO vs. OEM

Replacing a fuel pump doesn't have to break the bank. Here's how the costs compare:

  • OEM Yamaha pump: Typically $309.99 or more for the pump assembly alone
  • KEMSO aftermarket pump: Often priced around $79.98 for many models, with the same or better performance
  • Labor costs: If you have a mechanic do the job, expect to pay $150-$400 for labor, depending on your location and the shop's hourly rate

By choosing a KEMSO pump, you can save hundreds of dollars while getting a product that meets or exceeds OEM specifications. The lifetime warranty alone makes it a smarter investment.

Final Thoughts

Your Yamaha 115 4-stroke fuel pump is the heart of your fuel system. When it fails, your boat will not run right—or at all. By recognizing the symptoms early and replacing the pump with a quality unit, you can get back on the water quickly and with confidence. The KEMSO fuel pump is the clear choice for owners who want performance, reliability, and the peace of mind that comes with a lifetime warranty. Whether you tackle the installation yourself or have a professional do it, using a KEMSO pump ensures your Yamaha 115 will perform at its best for years to come.

For more information and to order your KEMSO fuel pump, visit: https://www.kemsoracing.com/


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