When your mower’s starter rope snaps, getting the engine running again requires installing a new pull string assembly correctly. Knowing how to replace pull string on lawn mower is a fundamental repair that saves you time and money. This guide provides clear, step-by-step instructions to get your mower running smoothly again.
A broken pull cord can feel like a major setback. However, the repair process is straightforward with the right tools and a bit of patience. You can complete this fix in under an hour, restoring your mower’s functionality without a costly trip to the repair shop.
How To Replace Pull String On Lawn Mower
Replacing a lawn mower pull string involves a consistent series of steps across most walk-behind mower models. The core process includes removing the starter assembly, rewinding the spring, threading the new rope, and reassembling the unit. Always prioritize safety by disconnecting the spark plug wire before beginning any work.
Tools And Materials You Will Need
Gathering the correct items before you start makes the job smoother. You likely have many of these tools already in your garage.
- Replacement pull cord (check your mower’s manual for correct length and thickness)
- Socket set and wrenches (typically need a 3/8″ or 1/2″ socket for the center nut)
- Screwdrivers (flathead and Phillips head)
- Needle-nose pliers
- Safety glasses and work gloves
- A sturdy work surface
Safety First: Preparing Your Mower
Before touching any part of the mower, you must ensure it cannot accidentally start. This is the most critical step in the entire process.
- Disconnect the spark plug wire from the spark plug. This prevents the engine from igniting fuel while you work.
- Tip the mower on its side, ensuring the air filter and carburetor side face upward to prevent oil and fuel leaks.
- Clear any debris from around the starter assembly on the top of the mower deck.
Locating The Starter Assembly
The starter assembly is the plastic or metal housing on the top of the mower engine that contains the pull cord handle. It is held in place by several screws or a single large center nut. You may need to remove a decorative shroud first to access it.
Step-By-Step Replacement Process
Follow these steps carefully to successfully install your new pull string.
Step 1: Remove The Starter Assembly
Use your socket wrench to loosen and remove the center nut or bolts securing the starter assembly to the engine. Gently lift the entire assembly off the engine shaft. Be cautious, as a powerful recoil spring is housed inside.
Step 2: Release Tension And Remove The Old Rope
Place the assembly on your work surface. Slowly let the pulley inside unwind to release all tension from the recoil spring. Once slack, you can untie or cut the knot holding the old rope inside the pulley and remove the broken cord completely.
Step 3: Wind The Recoil Spring
This step requires care. Turn the pulley in the direction it normally spins when the rope is pulled (usually clockwise) until you feel resistance. Then, turn it slightly further—about one full turn—to create tension. Use a pair of pliers to hold the pulley in place, preventing it from snapping back.
Step 4: Thread And Knot The New Rope
Feed one end of your new pull rope through the hole in the pulley. Tie a secure, bulky knot, such as a figure-eight or double overhand knot, on the end inside the pulley. This knot must be large enough not to pull back through the hole.
Step 5: Wind The Rope Onto The Pulley
While keeping tension on the spring with your pliers, carefully wind the new rope onto the pulley in the same direction the spring is wound. Leave about 6 inches of rope hanging out of the assembly’s rope exit hole.
Step 6: Reattach The Starter Assembly
Align the starter assembly back onto the engine shaft. You may need to engage the tabs on the assembly with slots on the engine. Secure it firmly with the center nut or bolts. Do not over-tighten, as you could crack the plastic housing.
Step 7: Attach The Pull Handle And Test
Thread the free end of the rope through the hole in the pull handle. Tie another secure knot. Before reconnecting the spark plug, give the cord a slow, gentle pull to ensure it retracts smoothly. If it does, reconnect the spark plug wire and test start the mower.
Common Challenges And Troubleshooting
Sometimes, you might encounter issues during the repair. Here are solutions to common problems.
The Recoil Spring Slipped Out
If the spring comes unanchored, it can be tricky to reset. You’ll need to carefully rehook the outer end of the spring into its notch in the housing and then rewind it. Patience is key here, and wearing gloves is recommended.
The New Rope Does Not Retract
This usually indicates insufficient tension on the recoil spring. You will need to disassemble the unit again and add another full turn of pre-tension to the spring before re-threading the rope.
The Rope Frays Or Breaks Quickly
Check the rope exit hole on the starter housing for any sharp edges or burrs. Smooth them out with a file or sandpaper. Also, ensure you are using the correct diameter and type of cord specified for your mower model.
Preventive Maintenance Tips
Taking care of your starter assembly can prevent future breaks and extend its life.
- Regularly clean around the starter assembly to prevent grass and dirt buildup.
- Lubricate the moving parts of the starter mechanism with a light machine oil once a season.
- Avoid yanking the cord at an extreme angle, which causes uneven wear.
- Pull the cord smoothly and steadily rather than with a sharp, jerking motion.
FAQ Section
How Much Does It Cost To Replace A Lawn Mower Pull Cord?
A replacement pull cord kit typically costs between $8 and $20. This is significantly less than a professional repair, which could cost $75 or more including labor.
Can I Use Any Rope To Replace My Lawn Mower Pull Cord?
No, you should use a dedicated lawn mower starter cord. It is designed to withstand high tension, UV exposure, and repeated pulling. Regular rope may fray or snap quickly.
Why Does My New Pull Cord Keep Getting Stuck?
A sticking cord is often caused by improper winding of the recoil spring or a misaligned starter assembly. It could also be due to a damaged pulley inside the housing that needs to be replaced.
How Often Should A Pull Cord Be Replaced?
There’s no set interval. A pull cord should last for many years with proper use. Replacement is only needed when it frays, becomes difficult to pull, or snaps. Regular inspection helps you spot wear early.
Is It Hard To Fix A Broken Pull Start On A Lawn Mower?
For most people, it is a moderately easy DIY repair. The process requires basic tools and careful attention to the recoil spring mechanism. Following a detailed guide, like this one, makes the task very manageable.
Replacing a lawn mower pull string is a satisfying and economical repair. By following these steps, you can restore your mower’s function and gain confidence in maintaining your outdoor power equipment. Remember to always put safety first by disconnecting the spark plug, and take your time with the recoil spring to avoid frustration. With the job complete, your mower will be ready for the next cut.