How To Start Lawn Mower Without Primer Bulb? The Ultimate Guide. Lawn mower priming bulb

How To Troubleshoot a Lawn Mower That Won’t Prime

If your lawn mower won’t prime, then you must have wondered whether it is possible to troubleshoot this commotion and, if possible, how to do that?

First, gather up all the tools and materials and check the condition of gas. Then, remove the backing plate, primer, primer bulb, gasket, and air box to inspect thoroughly. Clean, repair or replace the faulty elements. Reinstall all the internal component accurately and tighten all the connections securely.

Initially, the entire process might sound complicated, but if you thoroughly follow today’s guidance, it won’t be a difficult task to do. So, learn how to troubleshoot a lawn mower won’t prime.

What Causes the Problem?

If your lawn mower suddenly fails to prime, the most common culprit behind this trouble will be either a worn-out primer bulb or a defective fuel line. It can be either one or both of them to cause the priming difficulty or complete failure.

Besides these two, similar issues can arise due to lack of fuel or if gas turns contaminated or water got mixed with the gas.

Your lawn mower might experience priming difficulty due to a faulty gasket or air box.

Steps to troubleshoot a lawn mower that won’t prime:

Reportedly, it’s a common issue that almost every lawn mower user encounter sooner or later.

But imagine you are all set to mow your lawn or garden on a perfect day, and when you attempt to start the mower, it won’t prime as well as there’s no sign of fuel coming out. Isn’t that one of the most irritating situations?

The good news is that if you go online, you will find several consumer forums, blogs, and YouTube videos with various DIY ideas. But all of them might not be reliable and can worsen the situation.

Therefore, I have enlisted an easy-to-do yet effective troubleshooting method to fix such problems quickly:

Things you will need to troubleshoot the lawn mower won’t prime:

Have a look at the checklist of the required tools and materials for this particular troubleshooting task:

Tools Materials
Powered/Electrical Screwdriver Carburetor Gasket
Standard Mechanical Tool Box Air Filter Backing Plate W/ Primer
Bosch 1/4″ Impact Driver Carburetor Jet Cleaning Kit
Wire Primer Bulb Replacement
Safety Goggles Gloves

Step 1- Check the condition of the Gas level:

The first obvious thing to check is whether you have gas in the touring engine, and is it sufficient?

Before adding to your lawn mower, inspect whether the gas is contaminated or presence of water in the gas.

If you see that the gas looks contaminated or water got mixed with the gas, I highly recommend flushing out the gas.

If the gas is clean, but the level is low or insufficient, add more gas to the tank.

Step 2- Remove the Backing plate:

First, use an electric or power screwdriver to pull out the three 5/16 screws to take off the little backing plate.

Now check whether the backing plate is in a good or bad state, and if it is not in good condition, you might have to replace the Backing Plate.

However, if the plate is in good shape, let’s move forward and see the gasket on there.

Next, bring this whole thing over to the bench and ferry over there to work more comfortably.

This is the backing plate and now loosen up the gasket.

One common issue here, is that this gasket sometimes does not make a good connection right here on this little groove.

Step 3- Remove Primer Primer Bulb:

Sometimes these two screws get torqued down so tightly that it wraps the plastic.

Then, you will see a little screen with clips attached there as shown in the picture.

All you need to do is push those clips in. Thus, pull the primer out.

Once the top tab adjustment is done, you can slip a screwdriver under there. Now, you should be able to push out the primer bulb.

If the primer bulb looks damaged, replace the Primer Bulb.

If it does not look damaged but has debris, clean the debris out.

In case, you need to repair the primer bulb of your lawn mower, read the How to Repair a Lawnmower Primer Bulb article and follow the instructions.

Step 4- Take the Screen out clean the area:

After pulling out the bulb, you will see a screen in that hole.

Also, make sure that the air opening is not blocked.

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Now, you need to run a wire through here and push it right through there.

That wire will come out the other side if everything is clear as shown in the picture.

Next, you can spray a little bit of carp cleaner through there and blow it out with air.

After cleaning up everything, or replacing the faulty primer bulb, reinstall everything by following the previous steps.

Step 5- Checking the Gasket Air Box:

Another thing you need to check is the gasket, which mainly ensures everything is flush and air-tight.

But the worn air intake gasket does not let an air-tight seal come from the primer base to the priming port in the carburetor.

To inspect further, remove the plastic air box and check the gasket. If it looks faulty, replace the Gasket.

But if the gasket’s condition looks good, check the air box because sometimes it cracks where the gasket lays and causes improper seal trouble.

Undertaking such troubleshooting task can be hazardous if you do not have enough expertise. Therefore, always remember to read your lawn mower’s instructions manual before operating, servicing, or troubleshooting it. Also, make sure you have the minimum expertise to do this task alone.

Frequently Asked Questions: lawn mower won’t prime

What causes a primer bulb on a lawn mower to not fill up?

Such issues can occur due to defective gas lines, faulty primer bulbs, weak hookups, or problems with the carburetor.

Can you prime a no-prime lawn mower how?

Yes, you can. First, splash starter fluid directly into your mower carburetor via the air intake. Then, carefully remove the air filter cover and air filter. Now, spray starting fluid into the air intake nozzle. Replace the air filter, and reinstall everything in place quickly. Your mower should start straight away now.

How does a lawn mower’s primer bulb work?

Pressing the primer bulb produces a vacuum that sucks up the gas from the fuel tank via the fuel lines and into the carburetor. Thus, when you press the primer a couple of times, it starts supplying enough fuel to mix with air in the carburetor for combustion.

Final Verdict

Every once in a while, mower can fail to prime and cause trouble due to earlier explained reasons, but the good news is, it’s not too expensive, time-consuming, and complicated to fix this problem.

For better understanding and reference, I have explained the simplest way to troubleshoot your lawn mower that won’t prime. But remember, you can only get the best result if you thoroughly follow all the instructions without skipping a single detail.

How To Start Lawn Mower Without Primer Bulb? The Ultimate Guide

Gone are those days a long ago when people used to use their hands to mow the lawn. A lawnmower is an innovative machine that doesn’t only cut grass quickly but efficiently. It also ensures a beautiful and enchanting appearance. But all this is only possible when your lawnmower works smoothly.

So, How to start lawnmower without primer bulb?

To start lawnmower without primer bulb you need to follow the following steps-

  • Making Ready The Mower
  • Turning On The Parking Option
  • Looking For The Air Cleaner
  • Taking Off Screws
  • Taking Out The Air Filter
  • Using A Volatile, Flammable Liquid
  • Putting Back The Air Cleaner
  • Turning On The Engine

As a regular user of a lawnmower, it is needless to say how important the primer bulb is for this machine. Most old lawnmowers include a primer bulb since a carburetor covers a huge amount of space in a lawnmower.

Let’s get to the point. Do you know how to start lawn mower without a primer bulb, and is it actually possible? Yes! It is attainable, and you can do it independently if you know the right method.

In this post, we will share how to start lawn mower without primer bulb step-by-step. Scroll on!

  • What Is A Lawn Mower Primer And How Does It Work?
  • What Is A Lawn Mower Primer Bulb?
  • How does A Lawn Mower Primer Bulb Works
  • Step 1 —Making Ready The Mower
  • Step 2 —Turning On The Parking Option
  • Step 3 —Looking For The Air Cleaner
  • Step 4 —Taking Off Screws
  • Step 5 —Taking Out The Air Filter
  • Step 6 —Using A Volatile, Flammable Liquid
  • Step 7 —Putting Back The Air Cleaner
  • Step 8 —Turning On The Engine
  • Step 1 —Preparing Mower
  • Step 2 —Checking Primer Bulb
  • Step 3 — Removing Retaining Ring
  • Step 4 — Releasing Clips
  • Step 5 — Removing Primer Bulb
  • Step 6 — Cleaning Primer Bulb Casing
  • Step 7 — Installing New Primer Bulb
  • Step 8 — Attaching Retaining Ring
  • Step 1 —Identifying Press-Button Type Bulb
  • Step 2 —Preparing Mower
  • Step 3 —Pushing Bulb
  • Step 4 —Starting Engine
  • Step 5 —Repeating
  • Step 1 —Identifying Ignition System
  • Step 2 —Pumping Primer Bulb
  • Step 3 —Controlling Handle
  • Step 4 —Alternative Solution
  • What is a Corded Mower?
  • What is a Cordless Mower?
  • Which is Better?

What Is A Lawn Mower Primer And How Does It Work?

Before knowing how to start lawn mower without primer bulb, it is essential to understand what is a lawnmower primer is and how it works.

What Is A Lawn Mower Primer Bulb?

The construction of the primer bulb looks like a tiny rubber switch or bulb, which you will push. When you press the button, it releases prime to help to start the machine.

How does A Lawn Mower Primer Bulb Works

Having an idea of how the lawnmower primer works is essential. The best example to understand how lawnmower primer works could be the human body.

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You can take your heart as a pump. To move blood from your heart to every part of your body, you need a pump. So, the primer bulb is the pump for a lawnmower.

Without a primer bulb, you can start your machine.but not as efficiently as you do with a primer bulb.

How To Start Lawn Mower Without Primer Bulb? Step By Step Guide

The location of the primer bulb is between the engine and the gas tank, which is also called the fuel line. So what is the job of a primer bulb for a lawnmower? The main task of this component is filling fuel at the correct amount inside the carburetor while your lawnmower machine is cold.

Most manufacturers use either plastic or rubber to make primer bulbs. If you are wondering how to start lawn mower without primer bulb, just follow these below steps. It will merely take 10 minutes to accomplish this job.

Before knowing the procedure, let’s first learn what items you will need to complete this task.

Step-by-Step Guide: How to Prime a Lawn Mower without Primer?

Step 1 —Making Ready The Mower

Choose a flat and open space before starting the procedure. Your garden sideways can be a good option if the surface is smooth. This will be an easy and convenient task for you.

Step 2 —Turning On The Parking Option

Keeping your mower in the parking mode will stop it from starting accidentally. Though it is a pretty basic task, we are still reminding you so that you don’t forget.

Step 3 —Looking For The Air Cleaner

The air filter of a lawnmower is mainly located on the engine side. Before finding the air filter, the air cleaner chamber will be visible to you.

On the top of the air filter, you will see a cover. Several screws are on the air filter lid to make it properly connected with the engine body.

Step 4 —Taking Off Screws

Now, you want to loosen the screws using a screwdriver. And finally, remove them from their position and keep them in a safer place as you will need them again.

Step 5 —Taking Out The Air Filter

Now put your hands inside the air cleaner chamber and take out the air filter from it carefully. After removing it from the chamber, the air cleaner chamber becomes more visible to you.

Step 6 —Using A Volatile, Flammable Liquid

Different types of volatile, flammable liquid are available in the market. You can use a starter fluid, which many professional mechanics often recommends.

Spray the liquid inside the air cleaner chamber where you see a hole. Make sure you use it carefully — no fire is close to you.

Step 7 —Putting Back The Air Cleaner

So, you have already sprayed the liquid inside the chamber. Now, putting back the air cleaner in its previous spot is all you have to do.

Make sure you place the lid correctly and tighten the screws properly without overdoing them. Keeping the cover in a reversed position will prevent the free airflow, and it may clog up too.

Step 8 —Turning On The Engine

So, everything is done; now you want to start the machine. Hopefully, it will run smoothly. Now, you can use the lawnmower without a premier bulb.

So, these are all the steps you want to follow to get a clear idea about how to start lawn mower without primer bulb.

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  • Don’t forget to wear hand gloves and eyeglasses for optimal protection.
  • Check the lawnmower’s manual before using it. You will have a clear view of how each part works and how they are co-related.
  • Use the screwdrivers very carefully.
  • Kids should be closed to you while you are doing this work.

How To Replace A Craftsman Lawn Mower Primer Bulb?

So, you have learned how to start lawn mower without primer bulb. But having a primer bulb saves your time and gives your multiple benefits too. That’s why knowing how to replace a craftsman lawn mower primer bulb is essential.

Like other components, you may need to replace a craftsman lawn mower primer bulb after a certain time. You may see a cracking issue on the primer bulb due to long-time usage or sun exposure.

Before knowing how to replace a craftsman lawn mower primer bulb, you should know whether the primer bulb has become faulty or not. So, how will you learn? You will notice a gas leak issue, and also, it will not have adequate pressure after pressing it. Additionally, the rubber gasket of the carburetor may become a faulty float needle.

Replacing a lawnmower primer bulb takes only a few minutes if you know the right method. Plus, you don’t need so many tools as most of them might be available to you.

Let’s learn how to replace a craftsman lawn mower primer bulb step-by-step.

Step 1 —Preparing Mower

Before replacing the bulb, you want to keep the machine on a flat surface for easier work. Also, let the machine comes at a normal temperature if you used it recently.

Step 2 —Checking Primer Bulb

Most lawnmowers have the primer bulb on the right side. You want to go on that side and inspect it. The color of the bulb is either red or black. It may come with a retaining ring or not.

Step 3 — Removing Retaining Ring

If your primer bulb has a retaining ring, take it out straight by holding it carefully. Now, you can see how the primer clip attaches to the primer bulb behind it.

Step 4 — Releasing Clips

Remove the plastic clip by pushing the flathead screwdriver into it on the other side. Release the second clip in the same manner.

Step 5 — Removing Primer Bulb

Now, use your flathead screwdriver at the back of the released clip to ferret out the primer bulb. Finally, use a versatile tool like long-nose pliers to take out the primer clip and bulb.

Step 6 — Cleaning Primer Bulb Casing

Next, take a carb cleaner and spray it inside the primer bulb casing. However, as the place is pretty small, you can first apply the cleaner on cotton buds and rub them out inside it.

Step 7 — Installing New Primer Bulb

Now, attach the intact primer bulb clip over the intact primer bulb. Check out the circular area of your primer bulb, and make sure the tabs are lining outside of that area.

Lawnmower Primer Bulb Hack

Carefully place the primer bulb inside the primer bulb casing, and a 17mm socket is needed to mount the clip.

Next, you want to insert the socket inside the primer bulb casing by pressing internally as long as the clip is positioned perfectly.

Step 8 — Attaching Retaining Ring

Lastly, attach the retaining ring to the primer bulb if it is available.

That’s it! These are the required steps you will go through to have a complete idea of how to replace a craftsman lawn mower primer bulb.

How Do You Prime A Craftsman Platinum Lawn Mower?

What kind of lawnmower do you have? How do you prime a craftsman platinum lawn mower? This type of lawnmower includes a primer or a carburetor.

The main job of this primer is to supply air inside the carb. The carburetor includes a jet where gas is sent by the primer. Hence, starting a cold mower becomes a hassle-free task with the perfect mixture of air and gas.

Here we are mentioning “How do you prime a craftsman platinum lawnmower?” step-by-step.

How do You Prime a Craftsman Platinum Lawnmower?

Step 1 —Identifying Press-Button Type Bulb

As you own a craftsman platinum lawn mower, you are supposed to have a press-button type bulb on the carburetor. This type of bulb is flexible and effortless to use. Most of them have a red color, so identifying them is easy.

Step 2 —Preparing Mower

Before priming the lawnmower, make sure you keep the machine in a flat position so you can work conveniently.

Step 3 —Pushing Bulb

Now, you want to push the bulb 2-3 times. It will create enough pressure to supply the perfect amount of air and fuel mixture inside the curb.

Step 4 —Starting Engine

Now pull the starter to crank the engine. It should start with one or two attempts. If not, give it some rest for few seconds. Then try cranking again.

Step 5 —Repeating

If you failed to start the engine, you should try it when the temperature is lower. Do the priming and cranking steps again to run the machine.

Hopefully, you have got a clear view about “How do you prime a craftsman platinum lawnmower?”

How Do You Start A Briggs And Stratton Lawnmower?

A wide range of lawnmower engines is available in the market. Briggs and Stratton Lawnmowers are one of the most reliable machines that can start consistently. Hence, you don’t need to give much effort to start this handy mower—all you need is to provide a few pumps of the priming bulb to start it.

However, automobiles will show various types of problems over time. You want to address the problem soonest for smooth operation. You may face difficulty in starting it. How do you start a Briggs and Stratton lawnmower?

Here are the procedures you want to follow if you wonder, “How do you start a Briggs and Stratton lawnmower?”

Step 1 —Identifying Ignition System

Different lawnmowers have different ignition systems; check out the instruction manual to identify your mower ignition system.

Ignition systems with Prime’ N Pull or Smooth Start mechanism require prime the mower when it is in cold temperature.

However, if it has Smooth Start Plus or Ready Start mechanism, no prime needs to use for that particular engine.

Step 2 —Pumping Primer Bulb

Now reach to the primer bulb, which is located on the side of the primer bulb. A rubber lid is included on this bulb to cover it.

start, lawn, mower, primer, bulb, ultimate

You want to pull the bulb three times. Make sure you give a few seconds gap for each pull so that sufficient gasoline can get inside the carb.

Step 3 —Controlling Handle

If your lawnmower has a handle lever, you want to press it to release the mower brake. Hold onto the starter cord with both hands and pull acutely.

Continuing pulling until it does is the only way to make it happen. Even after trying several times, if the engine doesn’t work, you want to give it a rest for a few minutes.

You may smell gas. The flooding issue may have happened on the carb. Until you drain it, you may face difficulty in starting it.

Step 4 —Alternative Solution

If your lawnmower has a Ready Start Electric ignition system, you can start the engine by turning the ignition switch. You have no reason to take the hassle of priming. All you need is just releasing the key to involve the throttle, and the engine will start within seconds.

These are the required steps you want to walk through if you have a query about “How do you start a Briggs and Stratton lawnmower?”

Modern Small Engines – Why No Primer Bulbs?

Though you can start your lawnmower without primer bulbs, having one ensures fast and hassle-free engine running.

But modern small engines – why no primer bulbs?

Most primer bulbs are prone to be fragile or broken after a certain time. As a result, changing the bulb is the only option you have. Plus, starting your mower with primer bulbs is just a few more pulls. Nothing else!

Aside from that, most modern lawnmowers come with small engines, but they are power efficient. To save the space of the mower and make it less weighty, manufacturers are not using any primer bulb on modern small engines.

Hopefully, we got you covered on “Modern small engines – why no primer bulbs?”

Corded vs Cordless Lawn Mowers – Is A Cord Worth The Hassle?

Electric lawnmower either comes with cord or cordless. Unlike gas-powered lawnmowers, they make less sound, are hassle-free to maintain, and are less costly. Which one is better?

What is a Corded Mower?

It is one type of electrical lawnmower, which comes with a cord or cable. To run the machine, it needs a continuous power source from a socket.

What is a Cordless Mower?

It is the other type of electrical lawnmower, which doesn’t need any cord while operating. This type of mower features batteries where electric power is stored. The power will be used to cut your lawn.

However, you can also plug it in the charger source while running the machine. The battery will be recharged while you use the stored power to cut the grass.

Which is Better?

If your garden is huge, you can’t reach too far with a corded lawnmower. In that case, you need to attach an extra extension for it.

For a cordless lawnmower, you can’t reach anywhere as it does not require any cord. However, you want to make certain it has a sufficient amount of charge.

With a single charge, you can run a cordless lawnmower for up to 1.5 hours. Charging it more than one time will be necessary if your lawn is huge.

When the charge is low, your cordless lawn mower won’t work as fast as it would do for a fully charged battery.

What’s more, a cordless lawnmower has a slightly higher weight than a corded lawn mower due to the battery.

As for user convenience, a cordless lawnmower is far better than a corded lawnmower because you have no obstacle.

Lastly, the price of a cordless lawnmower is higher than a corded mower. When you consider all their features, both have pros and cons. So, it depends on personal preference to decide which one is better.

Final Thought

Having a primer bulb in your lawnmower gives you advantages. However, that does not mean you can’t start your lawnmower without a primer bulb—all you need is just to know how to start lawn mower without primer bulb correctly with a step-by-step method.

We have already shared all the precise details on how to start lawn mower without primer bulb. Hopefully, you have succeeded in starting your machine properly.

Last update on 2023-01-28 / Affiliate links / Images from Amazon Product Advertising API

Lee Safin was born near Sacramento, California on a prune growing farm. His parents were immigrants from Russia who had fled the Bolshevik Revolution. They were determined to give their children a better life than they had known. Education was the key for Lee and his siblings, so they could make their own way in the world. Lee attended five universities, where he studied plant sciences and soil technologies. He also has many years of experience in the U.S. Department of Agriculture as a commercial fertilizer formulator.

Thoughts on “How To Start Lawn Mower Without Primer Bulb? The Ultimate Guide”

Lawn Mower Primer Not Working: Reasons and Solutions

If you’ve ever tried to start your lawn mower only to find that the primer isn’t working, you know the frustration.

A damaged primer bulb or faulty fuel line will usually cause your lawn mower to fail to prime. Fuel contamination and water in gas can also cause similar concerns. Your lawn mower might experience priming difficulty due to a faulty gasket or air box.

If the lawn mower primer not working, this article will tell you why and how to fix it.

How Does The Lawn Mower Primer Work?

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Lawnmowers have smaller carburetors than autos. Small carburetors dry faster. The carburetor will be empty, preventing the lawnmower from starting. A primer solves this.

Primer pumps gas into the carburetor. Start the mower by delivering a fuel-air charge to the combustion chamber. The carburetor needs petrol to start the mower. Primers are either push bulbs or automated.

Bulb primers use physical strength, while the other works inside. They serve the same objective yet work differently. Bulb primers push gas to the carburetor. It directs tank fuel to the carburetor.

Another primer is automatic. The primer retains fuel when the mower is off. This fuel can get to the combustion chamber the next time you start the engine.

Both methods FOCUS on fueling the combustion chamber through the carburetor.

Reasons Behind Lawn Mower Primer Not Working (Fixes Added)

There are the main causes for a non-functioning primer on a lawn mower:

Blocked Fuel Line

If your lawn mower’s primer is not working, it may be due to a blocked fuel line. This is not uncommon in small engines, as dirt and debris can accumulate and clog the fuel line.

A clogged fuel line prevents the fuel from reaching the primer. This can be caused by dirt or debris in the tank, a kinked or damaged fuel line, or a fuel filter that is clogged or dirty.

The Fix

To fix this issue, you will need to locate the fuel line and unblock it:

  • Start by emptying any remaining fuel from the tank and disconnecting the fuel line from the carburetor.
  • Then, inspect the fuel line for any dirt, debris, or corrosion. If any is found, use a stiff wire brush to clean it out.
  • Next, check the fuel filter to make sure it is not blocked as well.
  • Finally, reconnect the fuel line, add fresh fuel to the tank, and try to start the lawn mower again.
  • If the primer still does not work, additional inspection and maintenance may be needed to diagnose the issue.

Primer Bulb is Not Being Squeezed

If the primer bulb on your lawn mower is not working correctly, it could be caused by a blockage in the fuel line. The blockage could be caused by dirt, debris, or even an air leak.

Flexible plastic or rubber is used to make priming bulbs and tubes, but over time these materials harden, break, and degrade.

The Fix

To diagnose the issue, you will need to check the fuel line for any blockages or leaks. If you find a blockage, use a small wire or needle to carefully remove it from the fuel line.

If you find an air leak, use a sealant to repair it. After doing this, try squeezing the primer bulb again to see if it works.

If the primer bulb still isn’t working, you may need to replace it. To do this:

If the primer bulb is too small, it will not be able to pull enough fuel into the carburetor to start the engine.

If it is too large, it will pull too much fuel and may cause flooding or other issues.

  • Once you have the right size, disconnect the fuel line from the primer bulb.
  • Unscrew the old primer bulb and replace it with the new one.
  • Reconnect the fuel line and try squeezing the primer bulb to see if it works.

If you have done all of the above and the primer bulb still isn’t working, the problem could be with the carburetor. In this case, you will need to take your lawn mower to a professional for further diagnosis and repair.

Carburetor Problem

Carburetor problems are usually caused by a lack of proper maintenance. The most common problems are dirty or clogged air filters, a clogged fuel filter, or a clogged carburetor.

A clogged carburetor can cause the fuel mixture to be too rich, leading to hard starting and possible stalling.

If the carburetor is not adjusted correctly, it can lead to issues such as poor performance, engine stalling, difficulty starting, and even an inability to start.

The Fix

  • Use a carburetor cleaner to remove any dirt or debris that has built up.
  • Then, use a small brush or compressed air to clean the jets.
  • Finally, if necessary, replace any worn or damaged parts.

Make sure the carburetor is properly adjusted according to the manufacturer’s specifications. This includes checking the idle speed, fuel mixture, and choke settings.

In addition, it is important to use the correct size primer bulb on the carburetor to ensure proper engine performance.

Fuel Contamination

If the fuel in your lawn mower has become contaminated, the primer bulb may not be able to draw fuel into the engine.

Contaminated fuel can contain dirt, water, or other debris which can block the flow of fuel from the primer bulb to the engine. If the fuel contains debris, the primer bulb may not be able to draw fuel into the engine for combustion.

If the fuel has been left in the mower for several months, it can also become stale and not combust properly.

The Fix

If fuel contamination or water in the gas is detected, dump the fuel tank and refill it with clean fuel. Replace polluted fuel lines and filters. This can ensure that the lawn mower is getting the right fuel combination and is not blocked or damaged by tainted fuel.

If the priming does not work, clean or replace the primer bulb and examine the fuel lines for blockages or damage.

Faulty Gasket

If the gasket on your lawn mower is faulty, then the primer will not work as intended. This is because the primer needs to build up pressure in the carburetor in order to properly mix fuel and air.

If the gasket is faulty, then the pressure will not be able to build up and the fuel and air will not be properly mixed.

The Fix

To fix this issue, you will need to replace the gasket. You can purchase a new gasket at most hardware stores or online.

To ensure a proper fit, make sure to follow any instructions that come with the new gasket.

Once the new gasket is installed, your primer should be able to build up the necessary pressure and mix fuel and air properly.

Maintaining a beautiful lawn can be a daunting task, especially if you lack the appropriate know-how and tools to handle the challenges that may crop up. Fortunately, LawnAsk is here to offer you an all-encompassing resource that covers everything you need to know about lawn care.

Priming a Lawn Mower: Easy Steps To Do It Right Every Time

Priming a lawn mower can be a bit intimidating for first-time lawn mower owners, especially when they haven’t encountered this before.

In this complete guide, we’ll discuss how to prime your lawn mower, its importance, and other related details.

How To Manually Prime Your Lawn Mower?

To manually prime your lawn mower, simply add fuel to the carburetor of the mower when there is no fuel. Some lawn mowers do this process automatically while others do not. A manual mower primer requires more attention due to the dedicated primer found on the carburetor.

Just by the term alone, priming the lawnmower should be the first thing to do when cutting grass. Here are the steps in priming your lawn mower:

– Find the Primer Bulb

Manual primers can vary in design, but they all have one factor in common: they are found on and near the carburetor. Manual primer bulbs are usually identified as clear rubber buttons that are attached directly to the carburetor. Sometimes, manual primers are also attached to a short fuel line that connects to the carburetor.

Priming small engines is always important, especially the ones found in most lawnmowers. The carburetors found in the engines are not sealed, which allows fuel to evaporate after some time and leaves the part dry.

Left in this condition, the carburetor will not function optimally. Even when the starter is pulled forcibly and repeatedly, the lawnmower’s engine won’t start. The carburetor needs fuel to ignite, and without it being primed, there is no pressure for it to pull fuel.


To resolve this, lawnmower manufacturers usually place a primer bulb as a manual solution to add fuel to the carburetor. Other models have an automatic internal inertia primer that works to power the engine by keeping some fuel inside.

When the manual primer bulb is pressed, fuel is driven to the carburetor. This process works by sucking the fuel through the gasoline system. Generally, lawnmowers use fuel pumps that rely on the pressure created by the engine of the lawnmower. When the engine doesn’t start, then there will be no pressure.

– Prime Manually

After locating your lawn mower primer. give it a firm but gentle push. Some people recommend two pushes while others suggest four. However, the most optimal number of pushes is three. Most homeowners would agree that three pushes to the primer bulb will give it enough starter fluid to feed the carburetor.

– Power the Engine

Once you have primed the carburetor by pushing the lawnmower primer bulb three times, you can start your lawn mower.

Pull on the starter once or twice, and your mower should begin to start up.

How To Avoid Mistakes?

To avoid mistakes when priming your lawnmower, make sure to add enough fuel to the carburetor and don’t push the primer bulb too many times. Even if the priming process is so simple, it can still be quite easy to make mistakes and get the whole method wrong.

Priming a lawn mower does not require much thought or effort, but it does require knowledge. Let’s look at two possible mistakes that can be easily avoided.

– Under-Priming Your Lawnmower

There is a possibility that the carburetor will not be primed optimally. This means that not enough fuel has been injected into the carburetor. Most likely, you have pushed the primer bulb once or twice only.

When this happens, the lawnmower will have problems starting up, similar to when left unprimed. You can easily diagnose this problem when the engine does not start despite pulling on the starter cord several times. If it is very hard to pull the lawn mower’s cord the causes might be different but there are some easy solutions.

To remedy this, simply push the primer bulb one more time. Once you do this, try starting the engine again. If enough fuel has been injected into the carburetor by the last push of the primer bulb, your engine should start without issues.

– Over-Priming Your Lawnmower

Over-priming can happen when the primer bulb is pushed too many times. This can result in the engines of your lawnmower becoming flooded by fuel. The fuel can spread into the combustion chamber, where it can gather and pool. Under this condition, the spark plug can get too wet and will not ignite. You can either wait for it to dry or you can locate the spark plug and dry it manually.

If you find that you have pushed the primer bulb more than necessary, don’t worry. Even if the engine fails to start, you can still solve this issue. Simply leave the lawnmower alone for about 10 to 20 minutes. The excess fuel will evaporate during this time, allowing the parts of your mower engine to dry out slightly.

Once the time has passed, start your lawnmower once again. This time, do not prime it. If your engine does not start, it might have evaporated the fuel too much. To correct this, start the priming process all over again but this time with just three pushes to the primer bulb.

How To Diagnose Why Lawnmower Primers Stop Working?

To diagnose why lawnmower primers stop working, you will have to figure out if it is because of a cracked primer bulb, a clogged fuel filter, or a cold primer. There are many reasons that can cause this condition, but these three are the most common.

Sometimes, the primer bulb of the lawnmower’s engine can stop working. The top three causes are found below.

– Cracked Primer Bulb

The rubber button can become damaged due different such factors as age, environmental exposure, or just wear and tear. As a result, the primer bulb can end up cracked, broken, or torn.

The damaged bulb will be unable to inject fuel into the carburetor’s combustion chamber. Consequently, the mower will have issues starting up. To resolve this, replace your primer bulb that has shown clear signs of damage.

– Clogged Fuel Filter

The primer bulb takes gasoline from the fuel filter into the carburetor. However, when the fuel filter is blocked or clogged, it can be difficult for the primer bulb to access the fuel. You might as well check and clean the air filter while doing this check.

This can result in the engine not starting due to the lack of fuel or starter fluid in the combustion chamber of the carburetor. To remedy this situation, either clean or replace the clogged fuel filter. Once this is done, try starting the engine of your riding lawn mower to see if it worked.

– Cold Primer

This usually affects automatic primers that have been idle for extended periods of time. The lack of activity can cause fuel to evaporate fully. The clearest sign of this situation is the inability of the engine to start because the combustion chamber does not have any fuel in it.

You can try cleaning the air filter and the fuel filter to keep everything in tip-top shape. Additionally, spraying the carburetor cleaner onto the part directly can help prime the automatic primer once more.


It is essential that homeowners learn to prime their lawnmowers in order to keep them in their prime condition.

For you to do the same, let’s recap what we’ve explored so far:

  • To prime the lawn mower manually, simply push the primer bulb three times.
  • If you have accidentally under-primed or over-primed, the lawnmower will not start and will still need to get primed again.
  • It is important to check the mower primer button or bulb for damages, which can interrupt the fuel injection to the carburetor.
  • Always check the air filter and the fuel filter for blockages and replace them when necessary.
  • For lawnmowers with automatic primers, ensure that the carburetor paths are clear and suitably primed.

Knowing how to prime your lawnmower is an essential skill, especially during the warm spring and summer months. Share your success stories with us by leaving us a comment or two!