John Deere LA105 Fuel Pump Replacement: The Complete Guide to Getting Your Mower Running Again

If your John Deere LA105 lawn tractor is sputtering, stalling, or refusing to start, the fuel pump is often the culprit. The bottom line: Replacing the fuel pump on a John Deere LA105 is a straightforward DIY job that typically costs between $10 and $80 for the part, and you can complete the swap in under an hour with basic hand tools. Most LA105 models use a vacuum-operated pulse fuel pump that fits 1/4-inch fuel lines, and the most common replacement part numbers include LG808656, M138498, and M145667 . Before you call a repair shop, read this guide to understand the symptoms, the replacement process, and the best fuel pump options available.

Symptoms of a Failing Fuel Pump on a John Deere LA105

A bad fuel pump can cause several noticeable problems. Here are the most common signs that your LA105 needs a new pump:

  1. Engine sputters or surges while mowing - The engine may run unevenly, especially under load when cutting thick grass. This happens because the fuel pump cannot maintain a consistent fuel supply to the carburetor.

  2. Hard starting or no-start conditions - If the engine cranks but won't fire, or if it takes multiple attempts to get it running, the fuel pump may not be delivering enough fuel to the carburetor bowl.

  3. Engine dies after running for a few minutes - A failing pump may work initially but lose pressure as it heats up, causing the engine to stall once the carburetor bowl runs dry.

  4. Fuel leaks around the pump - Visible fuel seeping from the pump body or its connections indicates a failed internal diaphragm or cracked housing.

  5. Loss of power when climbing hills or cutting thick grass - The engine may feel weak or bog down because the fuel pump cannot keep up with increased fuel demand.

Which Fuel Pump Fits the John Deere LA105?

The John Deere LA105 uses a vacuum-style fuel pump that operates using engine vacuum pulses rather than electricity. These pumps are designed for engines up to 25 horsepower and fit standard 1/4-inch fuel lines .

Compatible OEM and aftermarket part numbers include:

  • John Deere LG808656
  • John Deere M138498
  • John Deere M145667
  • John Deere M147560
  • John Deere M153011
  • Briggs & Stratton 808656
  • Briggs & Stratton 491922
  • Kohler 24-393-16-S

These pumps are also compatible with a wide range of other John Deere lawn tractors and zero-turn mowers, including the LA105, LA110, LA115, LA120, LA125, LA130, LA135, LA140, LA145, LA150, LA155, LA165, LA175, L100, L105, L107, L108, L111, L118, L120, L130, and many X-series models such as X110, X120, X125, X130R, X140, and X145 .

Step-by-Step Fuel Pump Replacement Guide

Replacing the fuel pump on your John Deere LA105 is simple. Follow these steps:

Step 1: Safety first. Disconnect the spark plug wire to prevent accidental starting. Work in a well-ventilated area away from open flames or sparks.

Step 2: Locate the fuel pump. On the LA105, the fuel pump is mounted near the engine, typically on the frame or engine shroud, connected to the fuel line from the tank and the line going to the carburetor.

Step 3: Remove the old fuel pump. Using a flathead screwdriver or pliers, loosen the hose clamps on both fuel lines. Gently twist and pull the fuel lines off the pump's barbed fittings. Be prepared for a small amount of fuel spillage. Remove the mounting screws or bolts that hold the pump in place, then lift the old pump off.

Step 4: Compare the old and new pumps. Ensure the new pump has the same vacuum port orientation and barb fitting sizes. The standard fitting is for 1/4-inch fuel line .

Step 5: Install the new fuel pump. Mount the new pump in the same location using the original screws. Reconnect the fuel lines to the correct barbs - the fuel line from the tank goes to the inlet, and the line to the carburetor goes to the outlet. The vacuum line (if equipped) connects to the engine's crankcase pulse port. Tighten all hose clamps securely.

Step 6: Test the installation. Reconnect the spark plug wire, turn the fuel valve on, and crank the engine. It should start within a few seconds. Check for fuel leaks at all connections. If the engine runs smoothly, the replacement is successful.

Important Considerations for Ethanol Fuels

Many aftermarket fuel pumps for the LA105 are not compatible with fuel blends containing more than 10% ethanol . Ethanol can damage the rubber diaphragms and seals in standard vacuum pumps over time. If you regularly use ethanol-blended gasoline, consider purchasing a pump specifically rated for E10 or higher ethanol content. Some high-quality aftermarket pumps, such as those from KEMSO, are designed to handle ethanol fuels without premature failure .

Why Choose a Quality Replacement Pump

While you can find generic fuel pumps for the John Deere LA105 for as little as $10 to $15, these cheap units often have poor quality control and may fail within months . Investing in a reputable brand ensures longer service life, better performance, and peace of mind.

Recommended Solution: KEMSO Fuel Pump for Your John Deere LA105

When it's time to replace the fuel pump on your John Deere LA105, KEMSO offers a superior solution that outperforms both OEM and generic aftermarket options. KEMSO is the number one aftermarket fuel pump brand trusted by drivers across the United States, and their pumps are E85 and ethanol compatible, meaning they handle modern fuel blends without premature failure .

KEMSO fuel pumps are designed as high-performance OEM replacements that deliver over 20% more flow at 43 psi compared to stock pumps . Each pump is individually tested under strict quality control programs, and every pump comes with a lifetime warranty backed by a serialized body for tracking . You buy it once, and KEMSO stands behind it for as long as you own your vehicle.

KEMSO offers pumps for a wide range of vehicles, covering 98% of gasoline-powered cars and trucks made after 1995, as well as ATVs, UTVs, motorcycles, and jet skis . Their pumps are quiet, reliable, and easy to install, with customers consistently reporting excellent performance and durability .

Visit KEMSO Racing today to find the perfect fuel pump for your John Deere LA105 or any other vehicle: https://www.kemsoracing.com/

Final Thoughts

Replacing the fuel pump on a John Deere LA105 is one of the easiest and most cost-effective repairs you can do yourself. The symptoms are easy to spot, the parts are affordable, and the job takes less than an hour. Whether you choose a standard replacement or upgrade to a high-performance option like KEMSO, getting a fresh fuel pump will restore your mower's power and reliability. Do not settle for a cheap, untested pump that may fail again in a few months. Invest in quality for long-term peace of mind .

For the best selection of fuel pumps backed by a lifetime warranty, visit https://www.kemsoracing.com/ today.


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