Direct Answer: How to Replace a Pull String on a Lawn Mower
To replace a pull string on a lawn mower, disconnect the spark plug wire for safety, remove the engine cover to access the recoil assembly, unwind the old starter cord from the recoil pulley, and thread a new cord of the same diameter through the pulley and handle while properly tensioning it. The process typically takes 30–45 minutes for most standard push mowers and requires only basic tools like a screwdriver and pliers. The exact procedure varies by mower brand and engine type, so consulting your owner’s manual for model-specific details is strongly recommended before beginning.
Understanding the Recoil Starter System
The recoil starter system, commonly called the pull string or starter cord assembly, is a mechanical device that manually cranks your lawn mower engine. When you pull the cord handle, it draws out the starter cord wound around a pulley inside the recoil assembly. This pulley connects to the engine’s crankshaft through a clutch mechanism that disengages once the engine starts. The recoil spring then automatically winds the cord back into its housing, ready for the next pull.
The recoil assembly typically sits beneath or to the side of the engine, often under a plastic or metal cover. On push mowers, you’ll usually find it on top of or beside the engine block. The system consists of several key components:
- Recoil pulley: The spool that the starter cord winds around
- Recoil spring: A tightly coiled metal spring that provides return tension
- Starter cord: The rope that connects the pulley to the handle
- Handle: The grip you pull to start the engine
- Housing: The case that contains all these components
Pull strings typically fail due to wear, fraying from repeated use, or breakage from sudden jerking. Unlike the recoil spring, which can last the life of the mower, the starter cord eventually wears out and needs replacement—usually after several years of regular use.
Tools and Materials You’ll Need
Before you begin, gather these items to ensure a smooth replacement process:
- Screwdrivers: Both Phillips and flathead (various sizes)
- Pliers: Standard slip-joint or needle-nose pliers for managing cord tension
- New starter cord: Match the diameter and length of your original cord (typically 3–4 mm diameter, 40–60 feet total length)
- Owner’s manual: Essential for your specific mower model
- Cord clamp or knot-tying material: To secure the new cord to the handle
- Lubricant (optional): Light machine oil for smooth pulley operation
When purchasing a replacement starter cord, bring your mower to the dealer or check your manual for the exact diameter and length. Common sizes are 3 mm, 3.5 mm, or 4 mm in diameter. Using the wrong size can cause the cord to slip in the pulley or wound too loosely, preventing reliable engine starts.
Safety Precautions Before Starting
Working with a recoil starter system involves potential hazards. Always follow these safety steps:
- Disconnect the spark plug wire: Remove the wire from the spark plug to prevent accidental engine starting while you’re working on the recoil assembly
- Allow the engine to cool: Wait at least 30 minutes after your last mow to let the engine cool completely
- Work on a flat surface: Place the mower on level ground or a workbench to prevent rolling
- Wear eye protection: Wear safety glasses in case the recoil spring suddenly releases
- Understand recoil spring tension: The spring inside the housing is under significant compression. If the housing cracks or the spring escapes, it can cause injury. If you’re uncomfortable working with compressed springs, consider professional service
- Avoid over-tensioning: An over-tensioned cord can snap suddenly or make the starter extremely difficult to pull
If your mower has a damaged recoil spring (you’ll notice the cord doesn’t retract at all or retracts erratically), professional service is recommended because replacing the spring requires managing dangerous spring tension.
Step-by-Step Replacement Process
Step 1: Remove the Engine Cover
Most lawn mowers have a plastic or metal shroud covering the engine and recoil assembly. Locate and remove the bolts or screws holding this cover in place using your screwdriver. Carefully lift the cover away to expose the recoil assembly underneath. Keep these fasteners in a safe place—you’ll need them later.
Step 2: Locate and Access the Recoil Assembly
The recoil assembly is usually a cylindrical or rectangular housing mounted directly to the engine block. Identify the recoil pulley inside (the spool where the cord is wound) and the starter cord handle attached to one end. Some mowers require you to remove additional bolts to fully expose the pulley; check your manual for your specific model.
Step 3: Remove the Old Starter Cord
Inspect how the old cord is attached to both the handle and the pulley. Most handles are secured with a knot inside a small chamber. Using pliers, carefully work the knot loose and remove the cord from the handle. Next, locate where the cord is attached to the recoil pulley (usually with a knot or crimp). Gently unwind the old cord from the pulley. If the cord is badly frayed or broken, you may need to pull it out in sections. Take photos during this process to remember the exact winding pattern.
Step 4: Thread the New Cord
Cut the new starter cord to the appropriate length (typically 40–60 feet, depending on your mower). Seal the cut ends by carefully melting them slightly with a lighter to prevent fraying. Tie a knot at one end of the new cord and attach it to the recoil pulley using the same method as the original (usually a knot or crimp). Check your manual for the specific attachment method your mower uses.
Slowly wind the new cord around the recoil pulley, following the same direction as the original. Count the wraps to ensure you’re winding it the same way. Leave enough cord unwound to reach the handle.
Step 5: Attach the Cord to the Handle
Thread the loose end of the new cord through the handle and tie a knot inside the handle chamber. The knot should be large enough that it cannot slip back through the opening. Pull the cord taut to ensure it’s secure and won’t slip during use.
Step 6: Test the Recoil Tension
Gently pull the cord handle a few times. The cord should pull smoothly and retract fully into the housing. If the cord feels too tight or doesn’t fully retract, the tension is incorrect. If it feels too loose or drags during retraction, you may need to re-wind the cord with one or two additional wraps around the pulley. Adjust until the pull feels natural and the retraction is smooth.
Step 7: Reassemble and Test
Replace the engine cover and secure all bolts or screws. Reconnect the spark plug wire to the spark plug. Move to a safe outdoor location, engage any safety switches on the mower, and attempt to start the engine. The pull cord should engage smoothly and the engine should crank normally. If the starter cord catches or feels wrong, stop immediately and review your work.
Model-Specific Variations
Briggs & Stratton Engines
Briggs & Stratton is the most common lawn mower engine manufacturer. Their recoil assemblies typically feature a metal housing bolted directly to the engine block. The pulley is usually accessible after removing two or three bolts. Briggs & Stratton starter cords are typically 3.5 mm in diameter and 48 inches long. These engines often use a spring-loaded latch on the handle that you’ll need to carefully manage when threading the new cord. Consult your model’s manual for exact handle attachment procedures.
Honda Engines
Honda lawn mower engines, commonly found on higher-end residential and commercial mowers, use more robust recoil assemblies. Honda starter cords are typically 4 mm in diameter. The recoil pulley on Honda engines often requires removal of the entire housing assembly (usually 4–5 bolts). Honda’s design is generally more enclosed, so take extra care to note the exact configuration before disassembly. Professional service is more common for Honda engines due to their complexity.
Toro Mowers
Toro brand mowers vary widely in engine type (many use Briggs & Stratton engines, while others use proprietary designs). Check your owner’s manual to identify your specific engine manufacturer. Toro’s recoil assemblies are typically straightforward to access, but handle attachment methods vary. Toro often uses a plastic cord guide that requires careful alignment during reassembly.
Self-Propelled and Riding Mowers
Self-propelled push mowers use the same recoil starter system as standard push mowers, but the assembly may be positioned differently due to the added transmission components. Access the recoil assembly from the side or rear of the mower rather than the top. Riding mowers often use electric starters instead of pull cords, but if your riding mower has a backup pull cord, the replacement process is similar to self-propelled mowers, though access may require removing additional panels or guards.
Testing and Troubleshooting
The Cord Doesn’t Retract Fully
If the new cord remains partially extended and doesn’t wind back into the housing, the recoil spring tension is insufficient. This usually indicates that you haven’t wound the cord tightly enough around the pulley or the spring itself is weakened. Add one or two more wraps around the pulley and test again. If the problem persists after re-winding, the recoil spring may need replacement—a task requiring professional service.
The Cord Feels Too Tight or Hard to Pull
Over-tensioning the cord makes starting difficult and risks cord breakage. If pulling the cord requires excessive force, you’ve likely wound it too many times around the pulley. Unwind one or two wraps and test again. The cord should pull with moderate, consistent resistance, not feel rigid or extremely difficult.
The Cord Slips or Spins Inside the Handle
This indicates the knot securing the cord to the handle is too small or has come loose. Remove the cord from the handle, tie a larger knot at the end, and re-attach it. Ensure the knot is positioned inside the handle chamber and cannot slip back through the opening.
The Engine Cranks But Doesn’t Start
If the starter cord engages correctly but the engine doesn’t fire, the problem is likely unrelated to the pull string replacement. Check fuel levels, spark plug condition, and air filter cleanliness. Reconnect the spark plug wire securely and try again.
The Cord Frays Again Quickly
Rapid fraying can indicate that the cord diameter is incorrect (it’s either too thin or the pulley is worn). Verify you’ve purchased the correct cord size. If the cord size is correct, inspect the pulley for sharp edges or wear. A damaged pulley should be replaced during professional service.
Frequently Asked Questions
How often do I need to replace a pull string on a lawn mower?
Starter cords typically last 5–10 years with regular use (weekly mowing during the season). Cords in heavy-use commercial settings may need replacement every 2–3 years. Proper care—storing the mower indoors, avoiding sudden jerking of the cord, and keeping the cord clean and dry—extends cord life. If you notice fraying or difficulty starting, replacement is due soon.
Can I replace just the cord without disassembling the recoil housing?
Most push mowers allow cord replacement without full housing disassembly. You’ll only need to remove the engine cover and access the pulley. However, some compact or specialty mower designs require removal of the housing itself. Your owner’s manual will specify the correct procedure for your model. If you cannot safely access the pulley without removing the housing, consult a professional.
What should I do if the recoil spring is broken or damaged?
A damaged recoil spring requires professional replacement because the spring is under dangerous compression inside the housing. Signs of spring damage include the starter cord not retracting, retracting erratically, or the handle remaining pulled out. Do not attempt to replace the spring yourself. Contact a lawn mower repair shop or authorized dealer.
Is it worth replacing the pull string myself, or should I hire a professional?
For most standard push mowers with Briggs & Stratton engines, DIY replacement is straightforward and saves $50–$100 in labor costs. If you’re comfortable with basic tools and following instructions, attempt the replacement yourself. However, if your mower has a complex engine design (Honda or commercial models), the recoil spring appears damaged, or you’re unsure about any step, professional service is recommended. A typical professional replacement costs $75–$150.
When to Seek Professional Service
Consider taking your mower to a professional technician if:
- The recoil spring is visibly damaged, rusted, or not returning the cord
- The recoil housing is cracked or broken
- Your mower model has a complex or unfamiliar recoil design
- You’re uncomfortable working with compressed springs or mechanical assemblies
- The engine still cranks abnormally after replacing the cord
- Your mower uses an electric start as the primary system and the pull cord is a backup
Professional lawn mower repair shops have the proper tools and experience to handle recoil spring replacement and complex engine designs safely. The cost of professional service ($75–$150) is justified if it keeps you safe and ensures proper operation.
