How to Replace a Pull Cord on Lawn Mower - A beginners guide

By: Author John Cunningham. Published: 2019/02/01 at 3:31 pm

Replacing a pull cord can be challenging, especially if the recoil spring gets loose. Taming a recoil spring can be like herding cats.

Follow these six steps to replace a lawnmower pull cord:

Remove pull assembly
Remove old cord
Replace cord
Wind spring
Fit pull handle
Refit pull assembly

Replacing the cord requires the removal of the pull start assembly. Some manufacturers, like Honda, make it easy. One screw, three nuts, and you’re in. Other mowers may take a little more work. If your spring is damaged or unravels, go ahead and buy a whole spring and pulley. They come already assembled; messing around with a recoil spring isn’t worth losing an eye.

This post covers pull cord replacement pretty well. However, if you need video help, check out “Pull cord faults video.” It covers diagnosing and repairing all the common pull cord problems, including pull cord replacement.

Choosing The Correct Cord

All cord isn’t the same; we’ll need to choose the correct cord to nail this repair successfully. Pull cord comes in different thicknesses; if you choose a card that’s too thick, the correct length won’t all fit in the pulley when wound in. A cord that’s too thin will work OK but will have a shorter life.

Cord – The thickness of the cord is important.

Replacing A Frayed Cord

The easiest cord to replace is the cord that hasn’t yet broken, just frayed. You still need to remove the pulling assembly from the mower; although it’s possible to do it in place, I don’t recommend it. Your mower may look different from the models used in the demo shots here, but no matter the repair procedure will be very similar to most mowers.

1 – Cut the correct length of the new cord and measure it against the old one. Don’t remove the old cord yet.

2 – Have sharp pliers and a flat screwdriver to hand. Pull the cord out all the way, secure the pulley, use a screwdriver to lock the spokes of the pulley, and stop it from retracting.

3 – Cut the old cord and discard it; now, feed in and knot the new one. Fit the pull handle and double knot. Remove your screwdriver and test. Now refit the assembly; that’s it, you’re done.

The complete repair for a broken cord is covered below with pictures, or check out “Pull cord troubleshooting” video here.

Replacing A Broken Cord

The cord-replacement process is just slightly longer. Remember, when the cord breaks, the pull assembly spring unloads, and so the spring must be wound up to reload it. In the guide below, I have removed the starter pulley from the assembly to fit the cord.

On most mowers, it isn’t necessary to remove the pulley from the housing. Instead, you can manage to feed the new cord into the pulley with a pulley in place; it’s just a little more awkward.

If you choose to remove the pulley, wear eye protection. Working with recoil springs can be dangerous; removing the pully from the assembly comes with the risk of the spring breaking free. I don’t advise working with the spring. If your spring does break free or is damaged/ worn, go ahead and replace the complete pull assembly.

They arrive fully assembled, just bolt them into place, and you’re done. Obviously, they’re a little more expensive than some rope but a lot less work. Anyway, here’s the replacement process. You can check out the “Pull cord troubleshooting video,” which also covers pull cord replacement.

If you need to have assembly parts delivered to your door, check out the Amazon link below.

Amazon Lawnmower Pull Start Parts

Pull & Twist – Pull the plug wire when working on your mower.

Remove Blower Assembly – The pull starter assembly lives in the blower assembly, and so we’ll need to remove it.

Remove – Some mowers, like Honda, allow access to the pull starter assembly without removing the blower housing. Nice!

Blower Assembly – Move to a workbench.

Pulley Cap – Remove the cap; this is a B&S assembly. Honda uses a left-hand thread here, meaning to remove turn clockwise.

Set cap aside

Set pawls aside

Pulley – Wear protective eyewear for this step. Remove the pulley by lifting it upwards gently; if the pulley doesn’t come out freely, don’t pull it, and the spring will unravel. Turn it clockwise to unhook it from its tang.

Replace – Replace the pulley if the spring is damaged.

Feed – If you have the old cord, use it to measure how much new cord you need. If you don’t have it, approx. two and a half meters does the job.

Go ahead and take the old cord from the pull handle. Feed one end of the new pull cord into the cord hole in the rim of the starter pulley.

Knot – Pull it through and knot it. I use a lighter to melt the nylon cut end and tidy it up.

Wind Cord – Wind cord tightly, clockwise around the pulley, and tuck it in neatly (Spring facing up).

Mark – It’s helpful to mark the rim where the pull cord ends with white paint. It helps to find it later.

Tab – Spring hook aligns with blower housing tab.

Fit – Align the spring hook with the metal tab on the pull start assembly housing; you’ll be fitting this blind.

Now seat it; confirm it’s seated by turning it anti-clockwise; you should feel the spring resistance. Fit both pawls and cap, and tighten the bolt.

3 Turns – Now wind the starter pulley anti-clockwise three to four revolutions, and align your white mark with the cord hole in the assembly housing.

You can’t let go, or the spring will unwind.

Feed – While holding the loaded starter pulley, locate the cord end that you marked earlier. Using a fine screwdriver, feed the cord end into the blower assembly housing cord hole.

Pull – Pull the cord through the hole and wrap it around your hand to prevent it from recoiling back in.

Handle – Burning and clipping the cord into a point helps the feeding process. Feed the remaining end into the pull handle, and use a fine screwdriver to help guide it.

Rubbing a small amount of oil on the end of the pull cord helps it slip through. When through the double knot.

Test – Pull to test; the pawls should shoot out when the cord is pulled and retract when the cord rewinds. Nice work, refit assembly; you’re done!

Pull Cord Troubleshooting

A broken cord is obvious, but some pull cord issues aren’t. Here are a couple of other common pull cord symptoms I hear a lot:

A pull cord doesn’t retract – usually a broken recoil spring
A pull cord doesn’t catch and turn the engine – usually means worn pawls

If your problem is a damaged recoil spring, then the pulley will need to be removed from the assembly; as said earlier, I would favor replacing the pulling assembly completely; working with a recoil spring is a lot like herding cats.

The pull assembly must be removed to fit new pawls, but it’s a simple job.

Replacing any of these is a job you can do without any special tools, and you’ll find all these repairs are covered in the “Pull cord troubleshooting” video here.

Cord Hard to Pull

If your pull cord is hard to pull (stiff), make sure the bail lever is held during the starting process. I know most of you are in no doubt about how to start your mower, but for anybody that’s a little rusty, check out “How to start a mower”.

Other likely reasons for a stiff pull cord are:

Engine brake – On or out of adjustment.
Blade obstruction – Dried grass, branches, etc., blocking blade.
Oil – Too much or the wrong type.
Hydro-locked engine – Caused by a faulty carburetor.
Excessive valve lash – Adjust clearance.
Engine damaged – Seized or bent crankshaft.
Broken flywheel key – Blade impact

Engine Brake

The engine brake, also known as the flywheel brake, is, as you know, controlled by the bail lever at the handlebars (most mowers), and it must be held to start the mower.

Its function is twofold – it grounds the coil, shutting down the engine, and it applies a brake pad to the flywheel, not unlike a bicycle brake. This stops the blade within 3 seconds of the bail lever release. The bail lever is operated by cable. If the cable is broken or needs to be adjusted, the brake will still be on or partly on as you’re trying to yank on the cord.

Brake – Check that the bail lever is releasing the flywheel brake. If not, check the cable for adjustment.

Blade Jammed

This is a simple one, but it is worth checking. Old dried grass and debris can collect under the mower; this can prevent the blade from turning and, consequently, the pull cord. Some mowers, of course, have a blade clutch, meaning the blade doesn’t move until you engage a lever. If this is your mower, then blade obstruction won’t apply to you.

Blockage – Grass and stuff stopping the blade from turning, the simple fix here.

Oil Level

You wouldn’t think too much oil could cause a stiff pull cord, but it will. Too much oil is also bad for the engine. It will cause it to smoke leak oil, and despite all that oil, it’s not being lubricated properly. So, the correct oil level is extremely important to the life of the engine.

This guide will show you all you need to know; you’ll be a pro 2 minutes from now – “Lawn mower oil check” or check out the video here.

Too Full – Too much oil or oil that’s too heavy will cause the pull cord to be heavy.

Hydro-locked

This is basically a cylinder filled with gas, and because a fluid can’t be compressed, the piston won’t move to give you a stiff pull cord. The gas enters the cylinder because the carburetor float needle seal is worn.

The fix – remove the spark plug to drain the gas and replace the needle or the whole carburetor. This guide will show you how to solve all these problems – “Lawn mower leaking gas.”

Important, you’ll need to change the oil, as the gas has likely leaked into the crankcase, which dilutes the oil, making it worse than useless at lubricating and cooling the engine. Fitting a fuel tap and turning the tap off when the mowers are not in use will prevent this from happening again. Check out “How to unflood a mower” video here.

Needle – The needle and float together to control gas flow to the fuel bowl.

Valve Lash

Incorrect valve lash will cause excessive combustion chamber compression, meaning it’s physically difficult to pull the cord against this pressure. I wrote this guide to help you solve that problem; it’s a step-by-step with pictures – Check and “Adjust valve lash,” or check out the video here.

Another possibility is a faulty compression release assembly. It’s fitted inside the engine, and its function is to release compression so that the operator can easily crank over the motor. Replacing it would require the total dismantling of the unit.

Check – Valve lash should be checked every season; it’s usually overlooked.

Flywheel Key

The flywheel key is a shear key, and when it shears, it puts the timing out on the engine. The key usually shears because the blade has hit something solid, and the engine has come to a sudden stop. The function of the key is to protect the crankshaft from twisting and to keep the flywheel to crankshaft alignment.

This guide will show you how to diagnose and replace the Shear key. Check out – “Flywheel key replacement” or check out the video here.

Shear key – Check the flywheel shear key.

Engine Damage

Lawnmower engines are very well designed and built, but poor maintenance, low oil, and abuse will kill them. A mower should have a tune-up every spring and an oil change every 50 hours of operation. Check the oil with every fill of gas.

Lawnmower engines are not designed to cut on slopes of more than 15 degrees; this causes oil starvation, which, as you know, can seize an engine. When an engine seizes, it fuses the metal components together, and the starter rope won’t pull. Check out “Mower tune-up” or check out the video here.

A seized engine can’t be repaired. Replacement engines are not difficult to fit, but sometimes, it’s better to just buy a new mower.

How to Replace a Pull Cord on Lawn Mower – A beginners guide