A snapped pull string on your lawn mower can be frustrating, but the fix is usually straightforward. Learning how to fix a pull string on a lawn mower is a common DIY task 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 diagnosis to the final pull. We’ll cover the tools you need, safety precautions, and detailed steps for different types of mowers.
How To Fix A Pull String On A Lawn Mower
Before you start taking things apart, it’s important to understand what you’re dealing with. The pull start assembly, or recoil starter, is a spring-loaded mechanism. When you pull the rope, it engages the engine’s flywheel to crank it. When you let go, the spring retracts the rope back into the housing.
A failure typically happens in one of three places: the rope itself snaps, the knot inside the pulley comes undone, or the recoil spring breaks or loses tension. We’ll address all these scenarios.
Tools And Materials You Will Need
Gathering your tools before you begin makes the job smoother. You likely have most of these items in your garage already.
- Replacement pull cord (lawn mower specific, check thickness and length)
- Socket set and wrenches (sizes vary by mower)
- Screwdrivers (flathead and Phillips)
- Needle-nose pliers
- Safety glasses and work gloves
- A pair of vise grips or a clamp
- Light machine oil or grease
- Scissors or a sharp knife
Essential Safety Precautions
Safety should always be your first priority when working with machinery. A simple mistake can lead to injury.
- Disconnect the Spark Plug: This is the most critical step. Remove the spark plug wire from the plug to ensure the engine cannot accidentally start while your hands are near the blade and recoil mechanism.
- Allow the Engine to Cool: If the mower was recently running, let it sit to avoid burns from hot components.
- Work in a Clean, Well-Lit Area: A clear workspace helps you keep track of small parts like screws and springs.
- Wear Eye Protection: Springs can slip and fly out unexpectedly. Gloves protect your hands from sharp metal edges.
Step-By-Step Repair Guide
Follow these steps carefully. Taking pictures with your phone before disassembly can be a helpful reference for reassembly.
Step 1: Access The Recoil Starter Assembly
First, you need to remove the starter housing from the top of the engine. This usually involves removing three or four bolts or screws that hold the plastic housing in place. On some models, the entire blower housing (the metal cover around the engine) must come off first. Keep all bolts and screws organized.
Step 2: Inspect And Diagnose The Problem
With the assembly in your hands, identify the exact issue. Is the rope completely broken? Has the knot inside the pulley come untied? Or is the spring not retracting the rope? Gently release any remaining tension from the recoil spring by slowly letting the pulley unwind. This is where caution is key to prevent the spring from jumpping out.
Step 3: Remove The Old Rope And Pulley
If the rope is broken, you’ll need to remove the remaining piece. Untie or cut the knot from the pulley’s anchor hole. To access the spring, you often need to remove the center nut or clip holding the pulley to the housing. Be prepared for the spring to be under tension; use vise grips to clamp the pulley to the housing before removing the center bolt to control its release.
Step 4: Wind The Recoil Spring (If Needed)
If the spring has lost tension or you removed it, it needs to be rewound. Place the spring in its channel in the housing. Using a clockwise motion, wind the spring tightly until it’s snug. Some assemblies have a tab that hooks into a hole in the housing. A common trick is to wind it about two full turns less than maximum to leave room for the rope to wind later.
Step 5: Thread And Knot The New Rope
Cut your replacement cord to the length of the old one, or a standard length (often 4-5 feet). Melt the ends with a lighter to prevent fraying. Feed the rope through the exit hole in the housing and then through the hole in the pulley. Tie a secure knot, like a figure-eight or double overhand knot, on the underside of the pulley. Pull the knot tight into its anchor slot.
Step 6: Wind The Rope Onto The Pulley
With the spring under tension and the pulley correctly positioned, wind the pulley in the direction opposite of the rope pull (usually clockwise) until the spring is tight. This pre-winds the spring. While holding the pulley to prevent it from spinning back, pull the rope through the exit hole and temporarily tie a large knot or use a clamp on the outside to keep it from retracting.
Step 7: Reassemble And Test The Starter
Reattach the pulley to the housing with its center bolt or clip, ensuring everything is seated properly. Place the housing back on the engine and secure it with the screws or bolts. Before attaching the starter handle, pull the rope out to ensure it retracts smoothly. Finally, tie the handle back on with a secure knot, trim any excess cord, and melt the end.
Common Issues And Troubleshooting Tips
Sometimes, the repair doesn’t go perfectly on the first try. Here are solutions to frequent problems.
The Rope Retracts Too Slowly Or Not At All
This usually indicates insufficient tension on the recoil spring. You’ll need to disassemble and wind the spring an additional turn or two. Also, check for rust or gunk in the spring housing and clean it. A light application of grease can help.
The Rope Is Hard To Pull Or Gets Stuck
This is often unrelated to the rope itself. The problem may be with the engine, such as a locked-up blade adapter or internal engine issues. Ensure the spark plug is disconnected and try turning the blade by hand to see if the engine cranks freely. Also, check that the rope isn’t rubbing against a sharp edge of the exit hole.
The Knot Keeps Coming Undone
Use a more reliable knot and always melt the end of the nylon rope to create a melted blob that acts as a stopper. Ensure the knot is seated fully in its dedicated anchor slot on the pulley, not just tied around a post.
When To Call A Professional
While this is a manageable repair, there are times when seeking help is the best course of action. If the recoil spring is broken or has jumped out of its track and you’re uncomfortable handling the high tension, a small engine shop can fix it quickly. If after reassembly the starter works but the engine still won’t crank, you may have a more serious engine problem that requires a mechanic’s diagnosis.
Preventative Maintenance For Your Pull Start
A little care can prevent future failures and extend the life of your lawn mower’s starter system.
- Lubricate Periodically: Apply a drop of light oil to the spring and pulley post during your annual mower tune-up.
- Avoid Yanking the Rope: Pull smoothly and steadily. Jerking the rope puts extra stress on the cord and knots.
- Store Properly: Keep your mower in a dry place to prevent rust on the recoil components.
- Inspect the Rope: Check for fraying at the handle or exit hole each season and replace it before it breaks.
Frequently Asked Questions
What Kind Of Rope Do I Use To Fix A Lawn Mower Pull Cord?
You should use a specifically designed lawn mower replacement pull cord. It is a durable, braided nylon rope that can withstand high tension and outdoor conditions. Using the wrong type of cord, like paracord or clothesline, can lead to quick failure and potential safety issues.
Can I Repair A Broken Pull Start Spring?
Yes, you can replace a broken recoil spring, but it is a more delicate task due to the high tension. Replacement springs are available for most models. The process involves carefully removing the old spring, cleaning the channel, and precisely winding the new one. If you’re not confident, this is a good job for a professional.
Why Does My Lawn Mower Pull Cord Keep Breaking?
Frequent breakage is often caused by a sharp or rough edge on the metal or plastic exit hole where the rope feeds out. Over time, this edge acts like a saw. To fix it, smooth the edge with a file or sandpaper and consider adding a small metal or plastic grommet to protect the rope.
How Much Does It Cost To Fix A Pull Start On A Mower?
If you do it yourself, the cost is minimal—usually just the price of a replacement cord, which is typically between $5 and $15. If you take it to a small engine repair shop, labor might cost between $50 and $100, plus parts, depending on your location and the shop’s rates.
Fixing a lawn mower pull string is a satisfying repair that gets your equipment back in action. By following these steps, you can tackle the job with confidence. Remember to always prioritize safety by disconnecting the spark plug, and take your time with the recoil spring. With this knowledge, a broken pull cord becomes a minor inconvenience instead of a major setback.