How To Replace A
Pull Cord

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

So how do you replace a pull cord? Follow these steps to replace a lawn mower pullcord:

  • 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, 3 nuts and your 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 replacing 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 replacing.

Cord Length

Pull cord comes in different thicknesses, if you choose a cord 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.
mower carburetor gumming

Cord

Thickness of 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 assembly from the mower, although it's possible to do it in place, I don't recommend it. 

 

(1) Cut the correct length of new cord, measure it against the old one. Don't remove the old cord yet.

 

(2) Have a sharp pliers and flat screwdriver handy. Pull the cord out all the way, secure the pulley, I use a screwdriver to lock the spokes of the pulley, stops it retracting.

 

(3) Cut the old cord, and discard, 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, your done.

 

Ride-on mower battery jumping

1

Measure the new against the old cord.

gas stabilizer

2

Lock the spokes of the pulley with a small screwdriver.

Ride-on mower battery jumping

3

Using a sharp pliers, cut the old cord out, feed in and knot the new.

Feed other end into the handle and double knot.

Replacing A Broken Cord

The process is just slightly longer if the cord is broken. Remember, when the cord breaks, the spring unloads, 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. Usually you can manage to feed the new cord into the pulley without removing the pulley from the assembly. 

 

If you choose not to remove the pulley, you must load up the recoil spring by turning it anticlockwise three turns. Then lock the pulley with the screwdriver as per the above guide, while you feed in and knot the cord, fit handle and double knot. Remove your locking screwdriver, check operation and refit, your done. 

 

If you don't fancy messing around with the cord, that's ok, Buy a pull assembly fully built, just bolt into place, your done. Obviously they're more expensive than some rope but a lot less work.

 

Mower engine Mower cover

Remove

Always pull the plug wire when working on your mower.

Your mower may look different, the symptoms and the repair procedure will be very similar.

Mower engine Mower pull assembly

Assembly

To make any repairs the assembly will need to be removed from the mower.

Test the assembly, the pawls shoot out when you pull the cord and retract when the cord recoils.

If your problem is a pull start that just isn't catching and turning over the engine. Simply remove the cap and replace the pawls. Examine all for damage including starter pulley.

Mower pull assembly

If your problem is a damaged spring then the pulley will need to be removed from the assembly.

Most pulleys wont need to be removed from the assembly to replace just the the cord. I find it faster, but you can choose not to, it swings and roundabouts.

Mower pull cord Mower pull starter Mower starter pawls

Remove

Have a container handy for small parts.

The pawls are made from plastic and when worn will cause the pull start to slip.

Mower pulley starter

Pulley

If your problem is a pull cord that doesn't retract. Replace the recoil spring.
Mower coil spring

Spring

This spring is damaged. You can purchase the spring on its own or with the starter pulley. I would fit the complete unit, as its not much more expensive but is a lot less difficult. Fitting the pulley is covered below.
Mower pull cord Mower pull cord

Feed

If you have the old cord, use it as a measure of how much new cord you need. If you don't have it, approx. two and 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.

Pull it through and knot it. I use a lighter to melt the nylon cut end, tidies it up.

Mower cord Mower cord

Paint

Wind the pull cord around the rim of the starter pulley, anti-clockwise with spring facing down.

It's helpful to mark the rim where the pull cord ends with white paint.

Helps finding it later.

Mower pull cord spring

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 its seated by turning it anti-clockwise, you should feel the spring resistance.

Fit both pawls, cap and tighten bolt.

gas stabilizer

3 Turns

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

You can't let go or the spring will unwind.

Mower starter pulley

Lock

While holding the loaded starter pulley, or locking it with a screwdriver, locate the cord end which you marked earlier.

Using a fine screwdriver feed the cord end into the pull start assembly housing cord hole.

mower starter assembly mower starter cord

Pull

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

mower cord mower cord

Handle

Burning and clipping it into a point helps the feeding process.

Feed the remaining end into the pull handle, use a fine screwdriver to help guide it.

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

When through double knot.

mower throttle lever mower carburetor

Test

Pull to test, the Pawls should shoot out when the cord is pulled and retract when the cord rewinds.

Nice work, refit assembly, your done!

Pull Cord Troubleshooting

A broken pull cord, recoil spring and worn pawls are common problems. Replacing any of these is a job you can do without any special tools. Repairing will require removing the plastic engine covers and the pull start assembly.

 

A broken cord is obvious, a pull cord that doesn't retract is usually a broken recoil spring, and a pull cord that doesn't catch and turn the engine usually means worn pawls.

 

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

 

Its function is two fold - 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 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.

 

Mower flywheel brake Mower flywheel brake

Brake

Check that the bail lever is releasing the flywheel brake.

If not, check cable for adjustment.

Blade Jammed

This is a simple one but worth checking. Old dried grass and debris can collect under the mower, this can prevent the blade from turning. 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.

 

Carburetor jet

Blockage

Grass and stuff stopping the blade turning, 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".

 

Mower oil level

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 giving you a stiff pull cord. The gas gets into the cylinder because the carburetor float needle seal is worn.

 

The fix - remove the spark plug to drain the gas, 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 not in use will prevent this from happening again.

 

Ride-on valve lash

Needle

Needle and float together 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 the problem, it's a step by step with pictures - Check and adjust valve lash.

 

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

 

Mower valves

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 flywheel to crankshaft alignment. This guide will show you how to diagnose and replace the Shear key. check out - "Flywheel key replacement".

 

Mower flywheel key

Shear key

Check the flywheel shear key.

Engine Damage

Lawn mower engine's 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.

 

Lawn mower 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. It's Toast!

 

Mower engine

Replacement engines are not difficult to fit but sometimes it's better to just buy a new mower.

Related Questions

Lawn mower pull cord loose? The cord is likely loose because the recoil spring has lost some of its tension, you can remove the pull assembly and wind the spring on a couple of turns to tighten, but replacing the spring is a more permanent fix.

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Auto Technician and Writer at | Website

John Cunningham is an Automotive Technician and writer on Lawnmowerfixed.com. I've been a mechanic for over twenty years, I use my knowledge and experience to write "How to" articles that help fellow gear-heads with all aspects of mechanical repairs, from lawn mowers to classic cars.