How To Bypass Primer Bulb On Weedeater In The Simplest Way 

Primer bulb is a popular household appliance that every household needs. Like other electronic devices, when it has to work for a long time without being warrantied carefully, it will stop working for a short time. In this case, you need to repair or bypass it to ensure that this primer bulb can operate well again. However, most people these days do not know how to bypass primer bulb on weedeater. 

You know, bypassing or repairing primer bulbs on weedeater is really necessary for your devices and maintaining their quality. You can call the expert or contact the manufacturers for this problem but you can also solve it by yourself in just some simple steps. If you know about its operation and some tips, you can repair it much more easily. 

That is the reason why we write this article. I think it is very useful and essential for everyone as it recommends you some ways to repair in detail. Besides, there are also some problems while you practise. Let’s read it now!

Firstly, we can go through some simple ways to bypass primer bulb on weedeater:

  • Fix a primer bulb for a weedeater
  • Replace a primer bulb for some kinds
  • Install a primer bulb on Mac 2827
  • Change the gas bulb
  • DIY carb for repairing primer bulb
  • How the primer bulb works for engine
  • Location of primer bulb on 4.5HP weedeater
  • Frequently asked questions
  • Conclusion

Fix A Primer Bulb For A Weedeater

A primer bulb for a weedeater, it stimulates the engine by filling gasoline in the carburetor. When you press, the primer bulb will spray an amount of gasoline that is combined with the air to start the operation system. Some kinds of primer bulb which are made from plastic or rubber or are used for a long time will be broken down, cracked and cannot be used anymore. In the situation you can use it again, it only gives the lowest quality. 

Therefore, replacing these primer bulbs and fixing it on the weed eater will be better and provide a good result. This problem has also taken a few minutes to complete. And these are some clear steps:

Firstly, you need to use the screwdriver to detach the screws that are attached to the primer bulbs in the metal table. Some of these screws are also diverse according to the kind of the primer bulb. The two most typical screws are flat-head or Phillips-head. After removing, you can place it in the area you can see. 

Secondly, you need to pull up the metal table to take it out from the primer bulbs. To do this more easily, you should hold the bulb tight and pull it straight away. If your metal plate is stuck, you only need to use needling pliers to solve this problem. 

The next step is cleaning and clearing up all detritus and oil that can stagnate on the surface of the primer bulb for the weedeater to avoid that it can get in the carburetor.

Finally, you place the new primer bulb in the centre area and you do not need to move the seat. Then adjust the screw holes and replace the metal table in the right place. Add two screws and then keep it tight with the screwdriver according to the clockwise. 

Replace A Primer Bulb For Some Kinds

Replacing is also the best answer if you do not know how to bypass primer bulb on weedeater. This method can help to save your money and also bring a better result and high quality for the primer bulb. There are many kinds of primer bulbs that you can replace.

On Ryobi 410R Tiller

As we know about the main function of the primer bulb on the engines, it helps to fill the carburetor with the gasoline that is blended with air and mist to start the engine. After a long time using, the primer bulb will be cracked or deteriorated and then the force is not strong enough to stimulate the engine. With this problem, we can replace the bulb for Ryobi 410R Tiller with just some simple steps that everyone can do. 

Step 1: Put the choke control in the middle of the Ryobi 410R Tiller. You should place it on the top, behind the engine and in the right side of the primer bulb

Step 2: Use the screwdriver with a flat blade to extract four screws that attach to the air filter and the silencer system behind the engine. Take it out straight away to remove and pick the filter out of the coverage.

Step 3: Use the screwdriver with a flat head to eliminate the two screws on the carburetor that is at the back of the air filter and then take the metal plate out of the carburetor.

Step 4: To avoid the leaking problem with the primer bulb, let a towel under the bulb to store the gasoline which can be leaked. Use the screwdriver to remove four screws on the primer bulb. Push the outside of the bulb via the mounting hold to extract. Clean it and the metal plate carefully with the towel.

Step 5: Try with the new primer bulb by pulling it from the back of mounting holes. Attach them to the bulb with four screws. Rearrange the metal plate and fix it with two screws. Use the new air filter and silencer system and connect it with four screws.

For A Sears Gas Blower

There are many products run by gas like office chair gas or gas blowers. The blowers run by gasoline are more comfortable and flexible than the electric ones. Because sometimes you use the electric blowers, the electric wire can limit you when you want to use it from a far distance. 

Meanwhile, the gasoline one comes with a rope and a primer bulb to offer gas and air to motivate the engine. Therefore, we should replace some primer bulbs to provide fuel for the carburetor. 

The first step is finding a flat surface to put your sear gas blowers in a desk or work table. If it has been used recently, you need to wait for the engine to cool down and then continue. After that, determine the position of the primer bulb on your gasoline blowers and observe the operation system from the back of this device. The primer bulb is between the air filter and engine which is on the left hand side of the coverage outside. 

Next, you need to remove the two screws on the metal plate of the primer bulb, use the Phillips screwdrivers to do this more easily. Remove the screws and the metal plate. If the plate has a little oil or dust, use a screwdriver with a flat head to pull it up. Hold the primer bulb tightly with your forefinger and thumb and then take it out. Clear all dust and dirt on the primer position by the towel to extract deposits quickly.

Finally, adjust the center position of your new primer bulb carefully, fix the distance between the bottom and the rim of this position. Change the ring while attaching the screws and mounting holes on the seat. Stick the two screws exactly as the beginning. 

Poulan String Primer Bulb

Poulan String primer bulb is also a kind of weedeater that you need to care for. You can use all the methods of how to bypass primer bulb on weedeater to solve this problem. This device can manufacture a lightweight gas from 8.8 pounds to the larger one 12.5 pounds. The primer bulb is known as a control system to start the engine.

Place the poulan string primer bulb on the flat surface and let it cool down if it has been used recently. Remove the sparking plug that is on the back of the engine to maintain the safety while you repair this device. Use the Phillips screwdriver to remove the two screws on the top of the engine and let them in other areas. Pull the engine up and turn off the engine. 

Use a small piece of tape to wrap around the fuel line that attaches to the primer bulb inside the engine. Use a point to determine the position more simply when you have to use two resemble lines. You need to detach the bottom of two fuel lines out of the primer bulb by the screwdriver with a flat head. Hold the primer bulb tight and use your hand to pull the bulb out of the engine.

Replace the new primer bulb into the old position and continue adjusting until you hear the sound when you insert it properly. Arrange the two fuels in the engine. Insert the engine in the poulan string and fix it with the two screws. Recover the sparking plug and then you can try the device again.

For A Model 770R

With the model 770R, I have found the connection map of this model through an interesting website. It has some connections with the fuel line. 

In particular, this model comes with the primer bulb that connects to suction by a carb. It also has the connection between the fuel tanks to the bottom of the container. Then the primer bulb helps to release the fuel in the fuel tank. The main kind of fuel with a primer bulb is usually the gasoline that is mixed with the air to start the engine. 

The primer bulb removes the fuel and also takes the fuel back to the fuel tank. This connection ensures that the fuel will always be provided enough to offer for your usage. 

Install A Primer Bulb On Mac 2827

This McCulloch Mac 2827 is a kind of weed eater that can be used to remove grass and weeds in some small and difficult to reach areas. This device uses a 28cc engine that runs on gasoline and a primer bulb provides fuel to start this engine. The primer bulb is used several times when you motivate the engine so you need to install a new one to make the operation system run smoothly. 

This method is safe and brings high efficiency for your device and I think it is the best answer for how to bypass primer bulb on weedeater. 

Firstly, let the device on a large surface and remove the sparking plug to ensure the safety during the installation system. Use the screwdriver to remove all the screws on the air filter and take the coverage out of the primer bulb. Find a small can under the carburetor to store anything that is stuck into the fuel container.

Keep the primer bulb brace tightly and then discharge some tabs. Remove the primer bulb and the tabs from the air filter. Take the fuel line out from the back of the primer bulb. Prepare a new primer bulb to replace the old one, buy the primer bulb from some reliable stores and check carefully before buying it. If you buy a good primer bulb, it can be used for a longer time and have better results. 

Reconnect the fuel line from the back of your bulb and attach the primer bulb to the air filter as the beginning. Put the tabs and the air filter in the right positions and then fix it exactly with the screws. 

Change The Gas Bulb

If you are still wondering about how to bypass primer bulb on weedeater, you can apply this method for your device. It is changing the gas bulb. You do not need to buy a new one to replace the old primer bulb. All you need to do is change the gas bulb that provides fuel and gasoline to start the engine. This method is a bit more complex than other methods but it will bring you an amazing result. It is also quick and does not take too much time to do. 

On A Stihl Weed Trimmer FS 75

Stihl Weed Trimmer FS 75 is a weedeater with a curved shaft to clear some small areas that the lawnmower cannot reach. For this device, you also need to change the primer bulb as soon as it appears some broken indication like leaking fuel and not enough gasoline in the carburetor to start the engine.

Firstly, adjust the operating system’s turn to stop position and let this device on a large flat surface. Detach the sparking plug that is on the top of the engine and let it cool down before starting to change the primer bulb. Put a thermometer on the fuel line that is located on the back of your primer bulb and hold it tightly to stop moving the gasoline into the carburetor. Apply for the two fuel lines and take it out of the primer bulb.

Remove the two screws on the primer bulb and place it in an area that you can see. Take the primer bulb and the metal plate out of the weedeater. Hold the round head of the primer bulb with your finger and do the same with the metal plate. Then change the new primer bulb into the hole on the metal plate. 

After that, place the metal table in the right position and rearrange the screws. Fix it with the screwdrivers. Place the two fuel lines into the primer bulb and take the thermometer out of the bulb. Put the sparking plug as the beginning and start the engine again. 

On A Lawnmower

Primer bulb is also used to start the engine in the circumstances that your lawnmower does not have an electric system. More particularly, the primer bulb provides the gasoline for the carburetor to motivate the engine. 

Some of these bulbs can deteriorate when they are in the sunlight for a long time or be cracked during the usage. This problem can lead to gasoline leaking and not enough pressure to start the engine. Therefore, you need to change the primer bulb. It only takes you a little money and does not take much time to repair. 

With Brigg And Stratton Engine

To change the primer bulb for the lawn mower, you have to let it cool down and wear safety glasses. Look at the primer bulb on the right hand side of this device, it is black or red with the retaining ring. Hold the ring tightly if it has and remove the primer bulb. Keep the screwdriver with a flat head on the one side and push the plastic clip inside. Do similarly with the other side.  

Remove the primer bulb with the plastic clip inside. Clean the carburetor carefully and clear away all the deposits inside. Then replace the old primer bulb with the new one. Notice to place it into the right position and hold the retaining ring if your primer bulb has. 

With Tecumseh Engine

With this kind of engine, you also need to care about the safety before repairing by wearing glasses. Use the needle nose pliers to fix the primer bulb on the right hand side of the lawnmower. Remove the bulb outside and use pliers to cut it down. Add a metal tab into the plastic clips on the both sides of the primer bulb. Adjust these clips at the 10 o’clock and 2 o’clock position. 

Clean the carburetor and take all the dust away. Replace with the new primer bulb and let it face outside. Fix it with the socket and use a hammer to attach to this seat.  

DIY Carb For Repairing Primer Bulb

This is the cheapest method when you want to know how to bypass primer bulb on weedeater. It only takes you 15 to 20 minutes to repair. 

Firstly, remove the carb from your device and cut off the fuel lines. Remove the four screws that are on the bottom of your primer bulb and let it aside because when you finish repairing, you need to insert it into the right position. Then take the primer bulb out of the metal plate that attaches it to the engine. Clean it carefully to clear away all dirts and deposits that are stuck for a long time. Use your finger to push it through the plate from the back.

Look at the rubber around the primer bulb and ensure that the metal plate is covered around the rubber tip. Make sure all the nipples are placed in the straight line and then count the nipples. Take your finger out of the metal plate and use the scissors to cut one row on the nipples that you have counted. 

Try to push the rubber tip into the metal plate as you have done at the beginning and adjust it to fit right into the carb. If there is still a lot of extra space, your carb does not work well. Attach the rubber tip to the metal plate by the glue and ensure it can stick well. Use the glue as much as possible and then let it dry and check the stickiness.

If there is extra rubber, you can grind it off to fit into the metal plate. Now insert the new primer bulb into the engine. Rearrange it as the beginning and fix it with the screws. All the steps must be done exactly to avoid leaking fuel when the engine starts. Place the fuel lines into the right areas and check the operation of the primer bulb.

It likely does not work at the first time, try it again until you see the gasoline go through it. Then you can use it to start the engine.

How The Primer Bulb Works For Engine

Understanding the operation of the primer bulb also is a perfect method that you can use when you do not know how to bypass primer bulb on weedeater. People use it as a button to press when they need gasoline to start the engine and the primer bulb will help to move the fuel from the tank to the carburetor to support the operating system.


The main principles of the operating system is pressing the primer bulb and providing the gasoline and air for the carburetor to motivate the engine. You only need to press it once and then it can offer the fuel that can be used for all day.


Like other devices, when you use a primer bulb for a long time, you need to replace it with the new one to get a better result. For all kinds of weed eaters, you need to remove the air filter and the primer bulb that is on the back of the air filter. Pull the tabs that contain the retaining rings. Fill it with the new primer bulb and then rearrange the air filter in the right position again. 

Bad Problems For A Long Time Using

The primer bulb can have some problems or deteriorate when you use it for several times. If you use old fuel, it can harm your primer bulb. Old fuel is very popular nowadays and people find it easy to buy it when it is sold too much on the market. Notice that only use the new fuel for the primer bulb. It can help to increase the span of your device and also help to save your money.

Location Of Primer Bulb On 4.5 HP Weedeater

Determining the location of the primer bulb plays an important role in controlling the operation. This 4.5 HP weedeater can be started by hand or use the key to motivate the electric to start the engine. However, using a primer bulb will help you start the engine more quickly and exactly.


With the Lawn-Boy Silver Series 4.5 HP Lawn Mower, the primer bulb is located on the left hand side of the engine. You can observe the bulb from the back of the lawnmower. It is in front of the air filter and face outward and below the fuel tank. The primer bulb is black and made from rubber that has the same size as your thumb.

How It Operate 

The primer bulb provides the gasoline and the air for the carburetor. The ratio between these two fuels enables the sparking plug to inflame the fuel blend and motivate the engine when you start the engine by hand or use an electric key. You can add more gasoline to run the engine for a long time.

Use The Primer Bulb Properly

Before using the lawnmower, check the gasoline and the air that is contained in your carburetor and hold it for a second. If the engine cools down, press the primer bulb about three times to start the engine. In the situation the temperature outside is under 55 degrees, press it two more times. This is because the primer bulb does not work effectively in the temperature lower than 55 degrees. 

Use a key or the rope to adjust the handle and the lawnmower. If the engine is still warm or has been used recently, you should be careful when using it because the gasoline can be stuck in the carburetor. If you use the primer bulb again, your device will exceed fuel and cannot start.  

Need To Replace

The primer bulb will deteriorate for a long time. It can be worn out, cracked or broken and does not provide enough gasoline to motivate the engine. You need to observe the primer bulb regularly and replace it as soon as there are some appearances of cracks or holes on the bulb.

Frequently Asked Questions (FAQ)

Can You Bypass The Primer Bulb By Yourself?

Taking care of the primer bulb is very necessary and you need to do it regularly to ensure the high quality of your device. This activity is also quite easy and you can do it by yourself when you see it one time. So, how to bypass primer bulb on weedeater? We have shown you some simple principles in this article. You can read it to get more information and I think it is useful for you.

Which Situation Does The Primer Bulb Not Work?

If your primer bulb does not work well, it’s time to replace it with the new one. You need to check the fuel lines whether it cracks or deteriorates. It will let the air into the primer bulb and cannot provide the gasoline for the carburetor.

Does The Primer Bulb Need To Be Full Of Fuel?

The main function of the primer bulb is providing gasoline for the carburetor to start the engine so your primer bulb should be filled with fuel. Check the device frequently to find the problems to repair immediately.

Conclusion: Are You Clear About How To Bypass Primer Bulb On Weedeater?

Primer bulb is a necessary piece of equipment that all the weed eaters have to start the engine more quickly and simply. It helps to provide fuel for motivating the operation system so you need to check the bulb frequently whether it has some problems. In these cases, replace it with the new one to maintain the high quality for your device. Besides, you can also find some coolest weed gadgets when you do not want to use weed eaters.

Watch this video to know more information:

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