Lawn Mower Wont Pull

You go to start your mower, and the pull cord just won’t budge. It’s a common and frustrating problem that can stop your lawn care in its tracks. When your lawn mower wont pull, it feels like you’re fighting the machine. This guide will help you understand why and, more importantly, how to fix it yourself.

We’ll walk through the simple checks first, then move to the more involved repairs. With some basic tools and patience, you can often get your mower running smoothly again without a costly trip to the repair shop. Let’s figure out what’s holding you back.

This is the core issue. The pull cord assembly is what you interact with, but the resistance usually comes from deeper inside the engine. A cord that won’t pull at all indicates a serious mechanical bind. A cord that pulls very hard but doesn’t turn the engine over points to a different set of problems. We need to diagnose the root cause.

Safety First: Before You Start Any Work

Always disconnect the spark plug wire. This is the most important step to prevent the engine from accidentally starting. Remove the wire from the plug and secure it away from the terminal.

Let the engine cool completely if you’ve just tried to use it. Work on a flat, stable surface and make sure the mower is secure. Wear safety glasses and gloves to protect your hands from sharp edges and dirt.

Quick Initial Checks

Before we dive deep, let’s eliminate a few easy possibilities. Sometimes the solution is right in front of us.

Blade Engagement Lever: Is your mower a model with a blade engagement lever or clutch? Make sure it is in the disengaged (off) position. An engaged blade can create drag.
Wheels & Drive: If your mower has a self-propel feature, ensure it is disengaged. A stuck drive system can lock the wheels and, through the transmission, resist the engine turning.
Debris: Look under the deck. Is the blade jammed by a thick stick, wire, or a build-up of packed grass? Carefully (with gloves!) remove any obstruction.

Understanding the Pull Start System

The pull cord is connected to a pulley and a recoil spring inside the starter housing. When you pull, it turns the engine’s crankshaft via a set of engagement dogs or a cup. If any part of this system or the engine it’s trying to turn is seized, you’ll feel that stubborn resistance.

Common Causes and Step-by-Step Fixes

Here are the most likely reasons your mower won’t pull, listed from simplest to most complex to diagnose and repair.

1. A Fouled or Hydrolocked Engine

This is a very common cause, especially if the mower was stored on its side or if oil leaked into the combustion chamber. A cylinder full of liquid (oil or fuel) cannot compress, locking the engine solid.

How to Fix a Hydrolocked Engine:

Remove the spark plug. This is your first major diagnostic step for any hard-pull issue.
Now try to pull the cord. If it pulls smoothly, you’ve confirmed the cylinder was locked.
With the plug hole pointing away from you, gently pull the cord a few times to expel any excess oil or fuel from the cylinder. You may see it spray out.
Clean and re-gap the spark plug, or replace it if it’s fouled. Reconnect the wire.
Before reinstalling the plug, check the oil level. If it’s overfull, drain to the correct level. Use the dipstick, don’t just guess.

2. A Damaged or Bound Recoil Starter Assembly

The starter mechanism itself can fail. The recoil spring can break or jump out of its track. The pulley can crack or the cord can fray and jam inside the housing.

Inspecting and Replacing the Recoil Starter:

Remove the starter cover. This usually involves a few screws on the top of the mower engine shroud.
Carefully note how the spring is seated before disassembling. Better yet, take photos with your phone.
Inspect the cord for fraying. Check the pulley for cracks. See if the spring is intact and seated correctly.
Often, it’s easier and safer to replace the entire starter assembly as a unit. They are relatively inexpensive and save the hassle of wrestling with a tense recoil spring.

3. A Seized Engine Due to Lack of Oil

This is the worst-case scenario. If the mower was run with little or no oil, the piston and bearings can overheat, weld themselves to the cylinder walls, and seize the engine permanently. The repair cost often exceeds the value of the mower.

Diagnosing a Seized Engine:

After removing the spark plug and confirming it’s not hydrolocked, try turning the engine blade bolt (with the spark plug still out). Use a socket wrench on the bolt that holds the blade.
If the blade and engine do not rotate even with significant force, the engine is likely seized.
You can try a last-ditch effort: pour a small amount of penetrating oil (like PB Blaster) into the spark plug hole. Let it sit for 24 hours, then try gently tapping the blade bolt with a mallet while trying to turn it. This rarely works, but it’s worth a shot before scrapping the mower.

4. A Bent or Obstructed Crankshaft

If the mower blade hit a solid object like a rock or a tree root, the impact can bend the crankshaft. A bent crankshaft will bind against the engine block. Also, check that the blade isn’t loose and wobbling, causeing it to hit the deck.

Remove the blade and inspect the crankshaft for obvious bends. Try to pull the cord with the blade removed. If it pulls freely, the issue was the blade itself being warped and contacting the deck.

5. A Faulty Flywheel Brake or Key

The flywheel is the heavy wheel on top of the engine. It has a small key that aligns it perfectly on the crankshaft. If this “shear key” breaks (often from a blade strike), the flywheel timing is thrown off and it can bind against other components.

Additionally, the flywheel brake (the lever you hold down to start the mower) can malfunction and not fully release. Inspect the brake pad and cable for proper operation. This requires removing the engine shroud, so refer to your manual for specific steps.

Step-by-Step: The Full Diagnostic Process

Let’s put it all together in a logical order. Follow these steps to systematically find the problem.

Disconnect the Spark Plug Wire. Never skip this.
Check for External Obstructions. Look under the deck for jammed debris. Ensure the drive and blade controls are disengaged.
Remove the Spark Plug. Try pulling the cord. If it pulls easily now, you had a hydrolocked cylinder. Clean the plug and check oil level.
Remove the Blade. Try pulling the cord again. If it works now, your blade was bent or the crankshaft is bent where the blade mounts.
Inspect the Recoil Starter. Remove the starter cover. Check for a broken spring, frayed cord, or damaged pulley. Manually try to turn the engine via the blade bolt with the starter disconnected.
Check the Flywheel Area. If you’re comfortable, remove the engine shroud to visually inspect the flywheel and brake mechanism for obvious damage or misalignment.
Assess Engine Seizure. If, after all this, the engine will not turn via the blade bolt with significant wrench pressure, the engine is likely seized internally.

Prevention Tips for the Future

An ounce of prevention is worth a pound of cure, especially with lawn mowers. Here’s how to avoid the “won’t pull” problem next season.

Use Fresh Fuel: Old gas goes stale and leaves gummy deposits. Use a fuel stabilizer if you store your mower for more than a month, or just run it dry before storage.
Change the Oil Regularly: Check your manual, but typically once a season. Always check the level before each use. Running low on oil is the fastest way to kill an engine.
Store Properly: Store your mower upright in a dry place. If you must tip it, always tip it onto its side with the air filter and carburetor facing UP, never with the spark plug down.
Clean the Underside: After mowing, especially damp grass, scrape out the packed clippings from under the deck. This prevents corrosion and keeps the blade balanced.
Sharpen the Blade: A sharp blade cuts cleanly and puts less strain on the engine than a dull one that tears grass.

When to Call a Professional

Don’t be afraid to seek help. If you’re not comfortable with internal engine repairs, a small engine mechanic is your best bet. Specifically, call a pro if:

You’ve confirmed the engine is seized. They can give a final verdict and quote, but replacement is often advised.
You need to replace the flywheel key or diagnose internal timing issues. This requires precision.
The carburetor needs a rebuild after you get it running. This is a common follow-up issue.
You simply don’t have the time, tools, or confidence to proceed safely. It’s better to pay for a repair than to injure yourself or make the problem worse.

FAQ Section

Why is my lawn mower pull cord hard to pull?

A hard-to-pull cord is often due to a hydrolocked engine (oil or fuel in cylinder), a damaged starter mechanism, or excessive drag from a engaged drive system. Always start by removing the spark plug to test.

What does it mean when a lawn mower won’t pull start?

It means the engine’s internal components are mechanically bound and cannot rotate. This is a serious symptom that requires immediate diagnosis to prevent further damage from forcing it.

How do you fix a lawn mower that is locked up?

First, remove the spark plug to rule out hydrolock. If it’s still locked, check for a seized engine from lack of oil or a bent crankshaft from a blade impact. The fix may be an engine replacement if it’s seized.

Can old gas cause a mower not to pull?

Not directly. Old gas varnishes the carburetor and prevents starting, but it doesn’t typically cause a mechanical bind that stops the cord from pulling. However, fuel can leak into the cylinder and cause hydrolock.

My mower pull cord pulls but doesn’t engage. What’s wrong?

This is a different problem where the starter dogs or mechanism inside the recoil housing are worn or broken. The cord pulls freely but doesn’t catch to turn the engine. This requires opening up the starter assembly for inspection.

Dealing with a lawn mower that wont pull can be a test of patience, but it’s usually a solvable problem. By following the logical steps—safety first, then simple checks, then deeper diagnosis—you can identify the culprit. Most of the time, it’s a matter of clearing a fluid lock, replacing a $20 starter assembly, or removing a jam. Remember, regular maintenance is the key to avoiding most of these headaches. With your mower running smoothly again, you can get back to enjoying a well-kept lawn.