Murray M2500 Weed Eater How to & Troubleshooting Guide

murray m2500 weed eater how to and troubleshooting guide

Murray produces various gardening tools made of high-quality materials that allow for easy use and long-lasting service. The Murray m2500 weed eater is quite popular since it is easy to start and control, making it suitable for beginners and light trimming. Unfortunately, even this weed eater is from a well-known brand, and sometimes it will malfunction and develop issues during operation.

The most common issues with the Murray m2500 weed eater will be starting problems, sputtering, a smoking engine, among others. You can prevent most of these issues by performing regular maintenance such as cleaning the weed eater, filter replacements, proper fueling and carburetor adjustments. The article will help you diagnose the problems and give you their troubleshooting tips.

How do you start a Murray M2500 weed eater?

Starting the Murray weed eater can be a slight challenge for a first-time user; however, the guide below will quickly help you start the weed eater.

  • Place the weed eater on a flat surface away from any objects, people or pets.
  • Locate the red On/Off switch and press it to the On position.
  • Find the primer bulb on the side of the weed eater.
  • Slowly press and release the primer bulb ten times until the fuel line is full. Make sure you can see fuel in the primer bulb; if you cannot see the fuel, press and release the bulb until you see the fuel.
  • Move the blue choke lever to position one.
  • With the unit still on the ground, squeeze and hold the throttle control and then pull the starter rope five times with steady and fast motions.
  • While still holding the throttle control, push the choke lever to position two and then pull the starter rope three to five times to start the engine and then release the throttle control.
  • Allow the engine to start for about 30 to 60 seconds.
  • Move the choke lever to position three, and then allow the engine to continue warming up for another 60 seconds.
  • When the engine warms up properly, it accelerates without hesitation when you press then throttle control.
  • If the engine refuses to warm up, return the choker to position two and continue to give it time to warm up until it starts.

How do you string a Murray 2500 weed eater?

When using a string trimmer, eventually, you’ll have to replace the string. The string is a nylon trimmer line for cutting grass and weeds. The Murray M2500 has a dual line bump feed trimmer that uses a 0.080-inch diameter of the string. Here is how to replace the string.

  • Place the weed eater on a flat surface and make sure the power button is on the off position and let it cool off.
  • Clean the exterior of the weed eater using a rag to remove dirt and debris.
  • Remove the bump knob and spool by pressing the tabs on the sides of the trimmer head.
  • Locate the two starter holes on the spool.
  • Thread one end of the string into one starter hole and wrap about seven feet of the string in neat, straight rows to prevent jamming. Next, insert the end of the string into the retainer on the spool to keep it in place. Repeat this process with the second slot of the spool. Then snap the end of the second line into the retainer on the opposite side.
  • Thread both ends of the strings through each eyelet on the trimmer head.
  • Insert the spool into the trimmer head and pull about five inches of the lines through the slots to make sure they feed smoothly.
  • Reassemble the spool cap onto the trimmer head.

How do you adjust the carburetor in a Murray weed eater?

Fuel and air mix in the carburetor before the spark plug ignites them. Manually adjusting the carburetor on a weed eater is part of the regular servicing of the power tool to keep it performing at optimum. You may also need to adjust the carburetor when the wood eater is sputtering or stalling from loss of power. Carburetors have default settings, but you can make minor adjustments to the idle speed to increase or decrease engine speed. Fortunately, you can save some money by doing it yourself by following the guide below.

  • Set the weed eater on a flat surface.
  • Locate the two fuel adjustment screws on the side of the carburetor, high and low adjustment screws labelled “Hi” and “Lo”, respectively.
  • Use a Phillips flat head screwdriver to turn the screws clockwise until they are fully seated.
  • Adjust the high and low adjustment screws by turning both of them counterclockwise one complete turn with the screwdriver.
  • Press the power button to On position, press the primer bulb about three to four times, pull the choke and start the engine.
  • When the engine warms up, squeeze the gas trigger and turn the high adjustment screw counterclockwise. The engine should run smoothly without sputtering but not too fast to move the weed eater’s head.
  • If the engine sputters, turn the “Hi” screw clockwise less than a 1/4 turn until it smoothens out.
  • Release the trigger lever and allow the engine to idle.
  • Next, turn the low adjustment screw counterclockwise until the engine idles smoothly.

Why is my Murray m2500 weed eater not starting?

There could be a couple of reasons why the weed eater won’t crank when you press the throttle. Here are the most common causes and their possible solutions.

Fuel problems

Check the gas tank and ensure that it is full. The Murray 2500 weed eater is gas-powered. Therefore, it won’t start If It has no. If the gas tank is full, but you haven’t used the weed eater in a while, the fuel could be stale. Therefore you need to dispose of the old fuel and replace it with a new batch. If the fuel refill is new, the fuel might be still of low quality. The Murray weed eater performs better with gas with only 10% alcohol or is ethanol-free with a 40:1 gas to oil ratio.

Flooded engine

If the gas tank is full, observe the pungent odour of gas to indicate a flooded engine. Too much gas in the weed eater can prevent it from starting, and the mix ratio should be specific for the engine to start and function properly.

To unflood the engine;

  • Turn on the weed eater.
  • Switch off the choke lever.
  • While holding the throttle,  pull the starter rope several times quickly to dispose of the extra fuel from the combustion chamber.
  • Continue holding the trigger as the weed eater emits black smoke and then release the trigger.

If the engine has not flooded, the gas line could be kinked or bent such that it won’t allow gas to reach the engine.

Blocked air filter

Check the air filters for blockage. Over time dust and oil particles accumulate on the air filter and prevent air from entering the engine. There has to be sufficient oxygen for the engine to ignite to spark and keep the tool running. You can clean it with warm water and dish soap, rinse it several times to remove soap residue and then let the filter air dry before replacing it. If the air filter is too clogged, you can replace it with a new one.

Spark plug problems

A defective spark plug won’t ignite the gas and air mixture to start the weed eater. So, remove the spark plug from the weed eater and clean the electrodes using a plug cleaner to remove dirt.  Inspect the spark plug for cracks and damages, then replace it. You should also clean the spark plug every season and after prolonged use or about 25 hours for maintenance.


Dust and grime from the air and fuel will collect in the carburetor and cause it to become faulty. You can clean it to get it to function correctly. A carburetor with cracks or dents will also prevent the engine from starting and will require a replacement. The most obvious signs to look out for indicating a malfunctioning carburetor is black smoke when you try to start the weed eater, backfiring, overheating too quickly and the machine bogs down immediately after starting.

What causes my Murray m2500 weed eater not to stay running?

When the weed eater cannot maintain power to stay running, there is usually a problem with fuel quality, carburetor problems, insufficient air intake or exhaust problems. Here is how to troubleshoot your weed eater to get it running continuously.

  • Check the position of the choke lever. Ensure the choke lever is in the correct position when operating the weed trimmer. The choke delivers fuel to the engine to help with the ignition process when the engine is cold; therefore, the choke should be in the half choke position then turn the choke off when the engine starts. If the choke is on when the machine is running, it will cut out. Also, check if the choke lever is loose or stuck in the off position, preventing you from running the weed eater properly and replacing the choke.
  • Check the quality and flow of the fuel. When there is sufficient fuel, you will see the primer bulb filling with gas before starting the engine. Ensure the gas is pre-mixed and ethanol-free or has a minimum of 10% ethanol. If the oil has been in the gas tank for more than 30 days, it is stale and needs to be disposed of.
  • Adjust the carburetor if the engine stops when the weed eater is at high speed on idling. If it cuts off when running, adjust the H screw. Run the engine at full throttle, and use a flat head screwdriver to turn the H screw counterclockwise until the engine starts running without sputtering.
  • Check the fuel filter for blockage. A blocked fuel filter restrict sufficient fuel into the combustion chamber for ignition. Clean the filter or replace it with a new one.
  • Also, if the air filter is clogged, it will suffocate the engine when you try to run it at full speed. Clean the air filter or replace it.

Why isn’t my Murray M2500 weed eater primer bulb filling up?

The primer bulb is a plastic balloon that you press to draw fuel from the gas tank and deliver it to the carburetor. For your weed eater to start correctly, the primer bulb first has to fill up with fuel. If it does, the device will struggle to ignite. Here are some troubleshooting tips for a failing primer bulb in your Murray M2500.

Air leak

Sometimes the walls of the bulb or fuel lines will harden and break, which lets in air. When there is an air leak, you will notice that the bulb does not bounce out as it should when depressed. The best way to fix an air leak issue is to replace the bulb and fuel line.

Clogged gas lines

A short tube rubs from the gas tank to the primer bulb and then from the bulb to the carburetor. When dirt and grime from the fuel accumulate and clog these lines, they cause insufficient fuel to pass through, causing the primer bulb not to fill. You can clean out the clog, but you should replace the fuel lines seasonally, mainly if you use the weed eater in dusty conditions.

Loose connections

The fuel line from the primer bulb connects onto the carburetor with two elbow connector joints. Over time these tubes contract and expand severally, causing rips around the connections. The air leaks into the system, create weak suction by the primer bulb and prevents it from filling. Inspect the connection and apply some press fluid to make the connection airtight.

Why does my Murray M2500 weed eater smoke?

It is not a good sign when a power tool smokes, including the Murray weed eater. The causes for a smoking Murray weed eater include; poor fuel and oil mixture, blocked exhaust, dirty carburetor or leaking gas. The easiest way to troubleshoot this issue is by identifying the problem using the color of the smoke.

Improper gas/oil mixture

The correct fuel to oil ratio for the Murray M2500 weed eater is 40:1. It is best to get pre-mixed fuel since their measurements are more accurate than mixing the oil and fuel. The wrong mixture will interfere with proper combustion since too much oil will burn and produce blue smoke, damaging the engine.


If you notice black smoke emitting out of your weed eater, the first thing to check is the position of the choke lever. The starting procedure for your weed eater is for proper function. Your choke should be off after starting your engine. If the choke is on, switch off the weed eater, allow it to cool down, then start the weed eater again correctly and ensure the choke is off when operating it.

Bad gas

Other than the correct gas/oil mixture, your weed eater fuel should be fresh. An engine running on stale gas will sputter and produce thick black smoke due to incomplete combustion. You should not leave fuel in your weed eater for more than 30 days. Otherwise, it will oxidize, corrode and clog your engine. Remember to drain your fuel tank when storing it.

Malfunctioning carburetor

Problems with the carburetor will cause the weed eater to produce grey-white smoke. Carburetor issues can damage the engine beyond repair; therefore, you should immediately shut off the weed eater when you notice gray-white smoke. In addition, check the carburetor for dirt and fuel contaminants clogging it, which will require cleaning. Finally, if you live in high altitude areas, the carburetor could be struggling to adjust automatically; therefore, you should adjust it manually using a screwdriver.

Leaking fuel

If the fuel line is damaged and leaking fuel, it will pour onto the hot engine and cause smoking. Inspect the fuel lines and replace them. When replacing the lines, apply press fluid on the joints to allow the lines to stick to the ports correctly and avoid leaking.

Clogged muffler

Exhaust fumes from the engine are released to prevent the weed eater from overheating. The fumes move from the exhaust port to the muffler, and over time, they accumulate and clog the muffler. Sometimes the clog can ignite and produce smoke. Remove the muffler and clean it with a tube brush and rag. For prevention, clean the muffler after every 30 hours of use to reduce accumulation.

Why is my Murray M2500 overheating?

Gas-powered weed eaters will burn fuel and air to produce power and heat. However, improper combustion and a malfunctioning cooling system will cause the weed eater to overheat. Running the weed eater while it’s overheating will cause other parts to damage, forcing you to deal with high repair and replacement costs. The best way to stop it from overheating is to fix the source of the problem and prevent further overheating.

A clogged cooking system

The weed eater has a cooling system that brings cool air into the weed eater through the flywheel and pushes heat from the engine outwards to prevent overheating. If the cooling system is not working correctly, usually from clogging or a faulty flywheel and the heat will remain in the weed eater to cause overheating. Remove the driveshaft to access the cooling system and clean the starter system, flywheel and the engine’s cylinder cover to prevent the accumulation of trapped particles from the air supply.

Fuel issues

Poorly mixed fuel for your weed eater will burn at a higher temperature and produce excess heat. Ensure the pre-mixed fuel you use for your Murray M2500 has fuel to oil ratio of 40:1. You should also drain out the fuel if it exceeds 30 days in the fuel tank as it oxidizes and separates over time. If the oil is less than the recommended amount, the engine will overwork and overheat from reduced lubrication.

Clogged air passages

The air passages allow the entry of cool air and the removal of hot air to enable the engine’s cooling. If the air passages are clogging with dirt, the engine will overheat from reduced air circulation. Clean the air passages and air filter with warm water and dish soap, rinse them in cool water, and air dry.

Faulty carburetor

The carburetor controls the amount of fuel going into the combustion chamber. The engine will speed up and overheat when there is too much or too little fuel for combustion. Therefore, you should perform a carburetor readjustment to control the amount of fuel going into the engine.

Can you leave gas in a Murray weed eater?

You should never leave gas in the fuel tank for extended periods. Over time the gas will oxidize, begin to go rancid and damage the engine and other components. Even though most pre-mixed gas brands contain fuel stabilizers that prevent the fuel from going bad, it will start to expire in the fuel tank after 30 days because the weed eater is not airtight.

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Since most plants don’t grow during the winter months, you should drain the fuel tank before storage and store the weed eater away from moisture.

How to remove gas from the Murray M2500 weed eater

  • Turn the weed eater off and place it on a flat surface, then allow it to cool off completely.
  • Disconnect the spark plug boot from the spark plug to prevent the weed eater from starting accidentally.
  • Use a lint-free towel to clean the gas cap and prevent them from entering the fuel tank.
  • Turn the gas gap counterclockwise and remove it.
  • Lay a gas can on the ground and insert the transparent end of a siphon tube into the gas can.
  • Feed the other metal end of the siphon tube into the weed eater’s fuel tank.
  • Shake the tube up and down several times until fuel starts flowing from the fuel tank.
  • Once the fuel tank is empty, remove the siphon and replace the gas cap and spark plug boot onto the spark plug.


Generally, the Murray M2500 weed eater does not break down often or produce many issues. However, no machine is perfect. This article will help you know the proper fuel ratio, carburettor adjustment procedure and how to clean parts vulnerable to clogging in your Murray M2500. Also, regular maintenance will allow the weed eater to give optimum performance over a long time.