How To Change A Pull String On A Lawn Mower : Quick Pull String Replacement Steps

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When the pull string on your lawn mower snaps, the engine can’t start, but the fix is often simple. Learning how to change a pull string on a lawn mower is a fundamental repair that can save you time and money. With a few basic tools and some patience, you can have your mower running again in under an hour.

This guide will walk you through the entire process, from safely accessing the recoil starter assembly to winding the new spring and string. We will cover the tools you need, important safety steps, and tips for avoiding common mistakes.

How To Change A Pull String On A Lawn Mower

Replacing a broken pull cord is a straightforward task. The key is to work methodically and keep track of the parts. Before you start, make sure you have the correct replacement string, which is a specific type of durable nylon cord available at most hardware or lawn mower shops.

Tools And Materials You Will Need

Gathering everything before you begin will make the job smoother. You likely have most of these items already in your garage or toolbox.

  • A replacement pull string (check your mower’s manual for thickness and length, often 1/8-inch diameter)
  • A set of screwdrivers (flathead and Phillips)
  • A socket set or wrench
  • Needle-nose pliers
  • A pair of scissors or a sharp knife
  • A lighter or matches (for melting the cord ends)
  • A clean workspace

Essential Safety Precautions Before Starting

Your safety is the most important part of any repair. Never skip these steps, as they prevent serious injury.

  • Disconnect the Spark Plug Wire. This is the most critical step. Remove the wire boot from the spark plug to ensure the engine cannot accidentally start while your hands are near the blade.
  • Drain the Fuel or Run the Tank Dry. This reduces the risk of fuel spills and fire. You can also simply move the mower to a well-ventilated area away from ignition sources.
  • Work on a Flat, Stable Surface. Use a sturdy workbench or table if possible. If working on the ground, ensure the mower is stable and won’t tip.
  • Wear Safety Glasses. Small springs and metal clips can fly out when disassembling the recoil starter.

Step-By-Step Repair Instructions

Follow these steps in order to successfully replace your lawn mower’s pull string.

Step 1: Removing The Recoil Starter Assembly

First, you need to access the pull cord mechanism. This assembly is typically housed under a plastic cover on the top of the engine.

  1. Locate the bolts or screws holding the starter cover in place. There are usually three or four.
  2. Use your socket wrench or screwdriver to carefully remove these fasteners. Place them in a small container so they don’t get lost.
  3. Gently lift the entire recoil starter assembly off the engine. It may require a slight wiggle to come free. Be cautious not to yank it, as the pull cord might still be attached inside.
  4. Set the assembly on your work surface with the top facing up.

Step 2: Disassembling The Starter Housing

Now you can open the housing to see the spring, pulley, and the remainder of the old string.

  1. Flip the assembly over. You will see several more screws holding the two halves of the plastic housing together.
  2. Remove these screws and carefully seperate the housing halves. Take note of how the parts are oriented. A gentle pry with a flathead screwdriver may be needed.
  3. Inside, you’ll find a coiled spring, a pulley or spool, and the knot of the old pull string. The spring is under tension, so proceed with caution.
  4. Use needle-nose pliers to untie or cut the old knot securing the broken string to the pulley. Remove all pieces of the old cord.

Step 3: Preparing And Installing The New Pull String

This is the core of the repair. Taking your time here ensures a long-lasting fix.

  1. Cut your new nylon cord to the correct length. A good rule is to match the length of the old string, usually between 36 to 48 inches. It’s better to start a little too long.
  2. Use a lighter to carefully melt and fuse one end of the new cord. This prevents it from fraying and makes it easier to thread. Let it cool for a moment.
  3. Thread the melted end through the hole in the pulley or spool from the inside out. Pull through about 3 inches.
  4. Tie a secure knot at the end you just threaded. A double overhand knot or a figure-eight knot works well. Pull it tight against the pulley.
  5. Before winding, ensure the pulley can rotate in the correct direction for winding the spring (usually clockwise).

Step 4: Winding The Spring And Reassembling

This step requires the most care. The main spring stores the energy to retract the cord.

  1. Slowly wind the pulley to coil the spring. Follow the direction indicated inside the housing, typically clockwise. You should feel resistance as the spring tightens.
  2. Wind the spring until the hole in the pulley aligns with the exit hole in the outer housing. Do not overwind, as this can damage the spring or make it difficult to assemble.
  3. While holding the pulley in place with one hand, guide the free end of the new pull string out through the exit hole on the housing.
  4. Place the housing halves back together, ensuring the pulley and spring stay aligned. Reinstall and tighten the screws evenly.
  5. Pull the cord all the way out to check the spring’s tension and retraction. It should pull smoothly and retract fully. If it doesn’t, you may need to rewind the spring.

Step 5: Attaching The Handle And Final Assembly

You’re almost done. Now you just need to finish the cord and put everything back on the mower.

  1. Thread the free end of the cord through the hole in the pull handle.
  2. Tie another secure knot, leaving enough slack for a comfortable pull. Trim any excess cord, leaving about half an inch past the knot.
  3. Melt the trimmed end with a lighter again to seal the knot and prevent untying.
  4. Carefully place the entire recoil starter assembly back onto the engine. Align the screw holes and the notch that engages the engine’s flywheel.
  5. Reinstall and tighten all the cover bolts or screws securely. Do not overtighten the plastic screws.
  6. Finally, reconnect the spark plug wire. Your repair is complete.

Common Problems And Troubleshooting Tips

Sometimes, things don’t go perfectly on the first try. Here are solutions to frequent issues.

  • The Cord Doesn’t Retract: The spring likely became unseated or lost tension. You’ll need to reopen the housing and rewind it, ensuring the spring’s outer hook is secured in its notch.
  • The Cord Retracts Too Fast or Jerkily: The spring may be overwound or damaged. It may need to be relaxed slightly or replaced entirely.
  • The Cord Frays Quickly at the Handle: You may not have melted the end properly, or the handle has a sharp edge. Smooth any rough edges on the plastic handle and ensure a good melted seal on the cord.
  • The Starter Assembly Won’t Sit Flush: Check that the pulley is aligned and that the cord is not bunched up inside. Also, verify the engagement tabs are lined up correctly with the engine.

Preventative Maintenance For Your Pull Cord

A little care can extend the life of your new pull string and the entire starter mechanism.

  • Lubricate the spring occasionally with a light machine oil during seasonal tune-ups.
  • Always pull the cord straight out in a smooth, steady motion. Yanking it at an angle causes wear.
  • Keep the starter assembly clean from grass clippings and debris, which can grind down the cord.
  • Store your mower in a dry place to prevent rust on the internal spring and pulley.

Frequently Asked Questions

What Kind Of String Do You Use To Replace A Lawn Mower Pull Cord?

You should use a specific nylon replacement cord designed for lawn mower recoil starters. It is typically 1/8-inch in diameter and sold by the foot or in pre-cut kits. Do not use ordinary rope or twine, as it will not withstand the tension and friction.

Can You Fix A Broken Pull Start Cord Without Replacing It?

If the break is near the handle, you can sometimes re-thread and re-knot the existing cord, but this is a temporary fix. A frayed or broken cord is weakened and will likely break again soon. Full replacement is the most reliable solution.

Why Does My Lawn Mower Pull Cord Keep Breaking?

Frequent breaks are often caused by a sticking engine or a damaged recoil mechanism. The cord snaps because it meets too much resistance. Check that the engine isn’t seized and that the starter pulley spins freely. A worn or dry spring can also cause jerky retraction that strains the cord.

How Much Does It Cost To Have A Pull Cord Replaced?

If you take your mower to a small engine repair shop, the cost for a professional to replace a pull string typically ranges from $50 to $100, including parts and labor. Doing it yourself costs only the price of the cord, usually under $10.

Is It Difficult To Rewind A Lawn Mower Recoil Spring?

It can be tricky the first time, as the spring is under tension. The key is to work slowly and carefully, following the winding direction. Using needle-nose pliers to guide the spring can help. If the spring pops out, it can be reset with patience, but replacement springs are inexpensive if it becomes damaged.