What You Need to Do Before You Start

Replacing a pull string (also called a starter cord or recoil cord) takes about 30 minutes and requires no special skills—just the right tools and a clear workspace. The pull string sits inside the recoil starter housing on top of your mower engine. When it breaks or frays, the mower won't start because you have no way to turn the engine over.

Before you touch anything, disconnect the spark plug wire. This is the thick rubber boot connected to the spark plug on the side of the engine. Pull it straight off and set it aside. This prevents the engine from accidentally starting while you work. You do not need to drain the fuel or remove the mower deck.

Gather your tools: a socket wrench set (usually 8mm, 10mm, or 12mm depending on your mower), a screwdriver (Phillips or flathead, depending on your model), a new pull cord (buy the exact diameter and length for your mower—check the manual or bring the old cord to the hardware store), and a pair of needle-nose pliers. Work on a flat surface with good light.

Key Takeaways

  • Always disconnect the spark plug wire before opening the recoil starter housing to prevent accidental engine start.
  • The recoil housing is held on by two to four bolts on top of the engine; remove these and set them in a small container so you do not lose them.
  • The old cord is tied to a spring-loaded pulley inside; you will need to wind the spring tension back into the housing before threading the new cord.
  • The new cord is knotted at one end (inside the housing) and looped at the other end (the handle you pull); both knots must be tight or the cord will slip.
  • Test the pull action before you reassemble everything—the cord should retract smoothly and the handle should snap back into the housing.

Remove the Recoil Starter Housing

Locate the recoil starter on top of the engine. It is a round or oval plastic or metal cover with a handle attached. You will see two to four bolts holding it to the engine block. Use your socket wrench to remove each bolt, turning counterclockwise. Place the bolts in a small cup or container when ready—do not set them on the ground where you might lose them.

Once all bolts are out, gently lift the housing straight up and away from the engine. Inside you will see a spring, a pulley (the wheel the cord wraps around), and the old cord attached to the pulley. The spring is under tension, so do not force anything or let the pulley spin freely—it will unwind suddenly and pinch your fingers. Set the housing on your work surface with the pulley facing up.

Unwind the Old Cord and Manage the Spring

Look at where the old cord is tied to the pulley. It is usually knotted through a hole in the pulley or tied around a post. Use your needle-nose pliers to carefully untie or cut the knot. Once the cord is loose, slowly let the pulley unwind by hand, feeding the old cord out of the housing. Go slowly—the spring is trying to pull the pulley back, and if you let it spin freely it will snap back hard.

Once the old cord is completely out, you need to wind the spring back into the housing so it is ready for the new cord. Hold the pulley steady with one hand and use your other hand to turn the pulley counterclockwise (when viewed from above) about three to five full rotations. You should feel resistance from the spring. Stop when the spring feels tight but not over-wound—if you over-wind it, the new cord will be under too much tension and may snap.

Look for a small notch or hole in the housing rim. Once the spring is wound, align a notch or post on the pulley with that hole to lock the pulley in place. This keeps the spring from unwinding while you thread the new cord.

Thread and Knot the New Cord

Take your new pull cord and hold one end. This end will go inside the housing and be tied to the pulley. Thread the cord through the hole in the pulley or around the post where the old cord was attached. Pull the cord tight and tie a knot on the inside of the pulley—use a double knot or a figure-eight knot so it cannot slip. Pull hard on the cord to test the knot; it should not move.

Now feed the other end of the cord out through the opening in the housing where the handle attaches. This is usually a slot or hole in the rim of the housing. Pull the cord all the way through until about 4 to 6 inches remain inside the housing. The cord should move freely through the slot without binding.

At the end of the cord that sticks out, tie a loop or handle knot. Most mowers use a straightforward overhand knot with the cord doubled back on itself, creating a loop about 2 inches across. Tie it tight so the loop cannot slip. Test it by pulling hard—your hand should grip the loop firmly without the knot sliding.

Release the Spring and Test the Pull Action

Once both ends are knotted, you can release the pulley lock. Gently rotate the pulley clockwise (the opposite direction you wound it) to let the spring slowly unwind. The spring will pull the cord back into the housing. Watch the cord as it retracts—it should feed smoothly without twisting or bunching. If it binds, stop and adjust the cord path through the slot.

Pull the handle slowly and steadily. The cord should extend smoothly and the pulley should turn. Release the handle and it should snap back into the housing quickly. Do this five to ten times to make sure everything works. The cord should not stick, and the handle should return all the way into the housing with a satisfying snap. If the cord does not retract fully, the spring may not be wound tight enough—you will need to remove the housing again and add another half-turn of tension.

Reassemble the Housing and Reconnect the Spark Plug

Once you are satisfied with the pull action, line up the housing with the bolt holes on the engine. Lower it straight down and hand-tighten each bolt first to make sure the housing sits evenly. Then use your socket wrench to tighten each bolt in a crisscross pattern (like tightening a car wheel)—this prevents the housing from warping. Tighten firmly but do not over-tighten, which can crack the plastic or strip the bolts.

Reconnect the spark plug wire by pushing the rubber boot straight onto the spark plug until it clicks or seats fully. You should hear or feel a click. Give it a gentle tug to confirm it is seated.

Now test the mower. Pull the starter cord smoothly and steadily. The engine should turn over. If it starts, let it run for a few seconds and then shut it off. If it does not start on the first pull, try again—cold engines sometimes need two or three pulls. If the cord is hard to pull or does not retract, stop and check your work: the spring may be over-wound, the cord may be binding in the slot, or a knot may have come loose.

Common Mistakes to Avoid

The most common error is over-winding the spring. If you wind it too tight, the new cord will be under extreme tension and may snap the first time you pull it. Wind the spring just until you feel solid resistance, then stop. A second common mistake is tying the knots too loosely. Both the knot inside the pulley and the handle loop must be absolutely tight, or the cord will slip and you will lose pulling power.

Another frequent problem is letting the pulley spin freely while the spring is wound. This causes the spring to snap back violently and can pinch your hand or fingers. Always control the pulley with your hand as you unwind and rewind it. Finally, do not forget to reconnect the spark plug wire—without it, the engine will not fire even though the starter cord works perfectly.

Frequently Asked Questions

How do I know what size pull cord to buy?

Check your mower's manual for the exact diameter and length. If you do not have the manual, bring the old cord to a hardware store or lawn mower shop and they can match it. Common sizes are 3mm, 4mm, or 5mm diameter and 40 to 60 inches long. Buying the wrong size means the cord will not fit through the pulley hole or will be too short to reach the handle.

What if the spring breaks while I am working on it?

If the recoil spring snaps, you will need to replace the entire recoil starter housing. Springs cannot be replaced separately on most mowers. Order a new housing from the mower manufacturer using your model number, or take the mower to a repair shop. This is why controlling the pulley carefully is so important.

Can I use any type of cord, or does it have to be the original brand?

You can use any pull cord of the correct diameter and length—it does not have to be the original brand. Hardware stores and online retailers sell universal replacement cords made of nylon or braided material. Avoid thin string or rope; it will fray and break quickly. The cord must be strong enough to withstand repeated pulling.

Why is my new cord hard to pull even though I followed all the steps?

The spring is likely over-wound. Remove the housing again and rotate the pulley clockwise one more time to release some tension. The cord should pull smoothly with moderate effort—if it feels like you are pulling against a very tight spring, the tension is too high and the cord will snap soon.

Do I need to prime the engine before pulling the starter cord?

That depends on your mower model. Some engines have a primer bulb you press three to five times before pulling the cord. Check your manual or look for a small rubber bulb on the side of the engine. If your mower has one, prime it before testing the new cord. If it does not have a primer, just pull the cord normally.