- A pull cord that flops out slack and will not reel back in has almost always snapped inside the housing, which is a rope job, not a broken spring, and the fix costs a few pounds.
- A cord that has gone hard to pull is a different fault entirely: caked clippings under the deck or an engaged brake, not the recoil at all.
- Replacing the rope means winding the spring back up by hand, and the whole repair takes about half an hour with a screwdriver, pliers and a new length of cord.
The Cord Went Limp Mid-Pull and Now Hangs There, and You Are Staring at a Repair Bill You Do Not Need to Pay
You give the mower one last tug, the rope suddenly goes light, and the end vanishes into the hole. Now it hangs slack and will not spring back. It feels terminal, the kind of thing that means a trip to the repair shop and a bill to match. It almost never is. A pull cord that will not retract is one of the most common faults on a petrol mower and one of the easiest to put right at home. The part is a length of rope that costs less than a pint, and the job is over in half an hour if you have a screwdriver and a bit of patience.
Before you touch anything, pull the spark plug lead off the plug so the engine cannot fire while your hands are near the blade. On a petrol mower with electric start, take the key and the battery out too. Then work through the checks below in order.
First, Work Out Whether the Cord Is Broken or Just Stuck
The single most useful thing you can do is tell a slack cord apart from a stiff one, as they are two completely different problems.
If the cord has gone hard to pull, or will not move at all, the recoil is probably fine. What is stopping it is the engine itself. The rope turns the crankshaft, and the blade is bolted straight onto that crankshaft, so anything jamming the blade jams the rope. The usual culprit is a wedge of wet clippings that has set like concrete under the deck, or the operator-presence brake, the sprung bar you hold against the handle, not being held down. Tip the mower with the air filter and carburettor facing up so no fuel or oil runs into them, clear the packed grass out from under the deck, make sure the brake bar is released, and try again. Nine times out of ten a hard-to-pull cord frees up the moment the deck is clean.
If the cord instead pulls out and flops down without reeling back, or came away light in your hand, the rope has snapped inside. To understand why that stops it retracting, it helps to know how the starter works. Inside the housing is a flat, coiled spring, the same idea as a clockwork spring. Pulling the rope spins a pulley and winds that spring up tight; let go and the spring unwinds, spinning the pulley the other way and reeling the rope back in. When the rope breaks, the pulley has nothing to hold, so nothing winds the spring and nothing pulls the cord home. The good news hidden in that: a cord that will not retract is nearly always a broken or unthreaded rope, not a dead spring. The spring itself failing is rare.
Get the Right Rope, Then Open the Rewind Unit
Different mowers take different cords. A universal starter rope kit (£5 to £9, or about $5 to $12) covers most machines and comes in a few thicknesses. You can fit the thinnest rope to anything, but the thinner it is, the sooner it breaks again, so match the diameter to your mower where you can. Most walk-behind mowers use rope around 3 to 4.5mm (roughly 1/8 to 3/16in) thick and need about 1.5 to 2m (5 to 6ft) of it. The surest way to get it right is to take the old cord to a hardware shop and match it on the spot.
To reach the pulley, take the rewind unit off the top of the mower. It is usually held on by three or more screws, sometimes hidden under a shroud that has to come off first. If yours is riveted rather than screwed, drill the rivets out and refit later with small bolts and locknuts. With the unit off, flip it over, find the knotted end of the old rope, grip it with needle-nose pliers and pull it out. That same hole is where the new rope threads through.
Wind the Spring, Thread the Rope, Tie It Off
This is the step that looks harder than it is, as long as you do it in order. Put on a pair of leather gloves first; the rope and the spring edge can both cut you.
- Wind the spring by hand. Twist the rope pulley in the same direction it turns when you pull the cord. It gets harder as the spring tightens. Keep going until it will not turn any further, then let it back off about half a turn to one full turn, until the hole in the pulley lines up with the hole in the housing.
- Lock it. Wedge a screwdriver against the pulley so the spring cannot unwind while you work. Let go now and it spins loose and you start again.
- Point the rope end. With gloves on, melt the tip of the new rope with a match and give it a quick twist while it is soft to make a firm point. Nylon rope frays the moment it is cut, and a sealed point threads through the two small holes where a frayed end will not.
- Thread and knot. Push the pointed end through the hole in the pulley and the hole in the housing, tie a knot in it, warm the knot with the match and pull it tight so it cannot work loose.
- Let it wind on. Keep a finger on the pulley, ease the screwdriver out, and let the spring gently reel the rope onto the wheel. Trim any excess.
- Fit the handle. Thread the free end through the handle and tie a knot so there is a little tension on the rope when you let the handle go, which keeps it seated against the housing. Bolt the rewind unit back on and refit any shroud you took off.
Refit the spark plug lead, and the mower should pull and start as it did before. The most common way this goes wrong is letting the pulley snap back while you thread the rope, so the spring lets go and you have to rewind it from scratch. The screwdriver is what stops that happening, so do not skip it. The other slip is leaving the rope too long, so the handle will not sit against the housing; trim it back until it does.
When to Stop and Let a Workshop Take Over
There is one point where this stops being a home job. If the rope is sound and undamaged but the cord still will not retract, the fault is the recoil starter itself, and usually the flat spring has broken or slipped its anchor. A wound-up starter spring is under real tension and can fly out at your face if you prise the housing apart without knowing what you are doing, so this is the moment to walk away from the screwdriver. You have two sensible routes. Swap the whole rewind unit for a new one, which bolts straight on in place of the old assembly and runs £15 to £35 (about $20 to $45), or hand it to a repair shop, where a recoil rebuild is a quick job at around £30 to £50 ($40 to $65). Either beats buying a mower over a broken spring.
The line to hold onto is this. A slack cord that will not reel back is a rope you replace for the price of a coffee. A stiff cord that will not pull is a deck you clean or a brake you release. Only a cord that is perfect yet still dead points at the spring, and that is the one job worth paying for. Everything short of it, you can do on the back step in the time it takes the kettle to boil.
