A lawn mower should only act like it is running out of gas when it’s actually running out of gas. If you find there is still gas in the fuel tank, but your lawn mower is showing symptoms of being out of gas, then you’re going to have to stop and grab some tools. There are many reasons why this could be happening, and it will require some investigation. So, let’s dig in and discover what’s going on.
Lawn Mower looks like it is running low on gas (The Short Explanation).
Low gas levels in lawnmowers could indicate a problem with fuel delivery to the engine. Defective components within the fuel delivery systems can starve a lawn mower’s engine of fuel and show symptoms similar to the lawn mower having no fuel, or running out of fuel.
The Most Likely Causes of Your Mower Acting Like It’s Running Out of Gas When It’s Not
A lawn mower that acts like it is running out of gas is actually running out. With reduced fuel flow, the lawn mower’s engine will cough and sputter, then eventually stall. This is probably why you think it’s out of gas. These are the parts that might be preventing fuel reaching the engine.
- Gas Cap
- Fuel Lines
- Fuel Filter
- Fuel Pump
- Carburetor
Diagnosing the Gas Cap
Most likely, your lawnmower’s gas cap is vented. This means that the gas cap of your lawnmower is vented. If air can’t enter the vent and get into the tank, then a vacuum will form. This vacuum holds the fuel in the tank and makes the engine think it’s out of gas.
Remove your gas cap and inspect the vent. You will need to quickly fix any damage or obstructions in the vent.
Inspecting Fuel Lines
Fuel lines can block and become less efficient over time. Fuel lines can get clogged by junk and fuel. This can cause a decrease of fuel flow.
So, to check if the lines are causing you an issue, you’ll need to disconnect them and carry out an inspection. There are many ways to do it, but I prefer to pull the entire line out to see what is going on. Drain any fuel that may be left in your mower before you start.
If you take a look in your lawn mower, you’ll find several fuel lines. These can vary from lawn mower to lawn mower, but these are where you should look.
- Fuel tank to Fuel filter
- Fuel Filter to Fuel pump
- Carburetor Fuel Pump
To remove the clips holding fuel lines to different components, use a pair pliers. Next, twist the fuel line. A rag is necessary to remove fuel from the lines. After you have removed fuel lines, use a small brush to clean them. To find any debris in the lines, use a bottle brush.
You will need inspection of the fuel lines
Inspection of the Fuel Filter
A fuel filter is a great addition to your lawnmower maintenance list. A fuel filter protects components and prevents fuel from being contaminated with junk and impurities. A fuel filter is likely to fail if the lawnmower is acting as if it is running out of gas.
If your filter is transparent you can inspect the inner membrane to determine whether it has discolored. This means that the filter is performing its job. Unfortunately, not all fuel filters are transparent, which I’m sure some of you will find out.
Now, if you know you haven’t changed your filter in some time, then it would be a good idea to change it out and eliminate it from the list of potential causes. This could be the root cause.
Check the fuel pump
To test a fuel pump, you’ll be checking to see how fuel flows through it. To save time and prevent waste, check the filter first. These components are located in front of the pump. A clogged filter or expired filter could cause a failure of the pump.
First, remove your carburetor’s outflow fuel line using a pair of pliers. Place the fuel-safe container in your car. Next, turn the ignition key or pull the starter cable to turn the engine on. To monitor the fuel level, I recommend that you have some assistance.
Once the engine is started, fuel should flow from the fuel line into the container. The fuel should flow smoothly. If the fuel spits out or doesn’t flow at all, then you probably have a bad pump.
The following tools can be used to inspect the fuel pumps
- Fuel-Safe Container
- Pliers
Carburetor Jet Inspection
You’d be amazed at the many symptoms of a bad carburetor. A bad carburetorjet is one of these symptoms. The carburetor jet is responsible for vaporizing the fuel at a precise level, and injecting the fuel into the cylinder heads. Fuel gum and small particles can block the flow of fuel.
This means even the smallest obstruction can cause your lawn mower to act like it’s running out of gas. So, to inspect the carburetor, you’ll need to remove the jet and look for blockages and anything causing an obstruction.
If you take a look at the bottom of the carburetor, you’ll find the fuel bowl. A socket wrench can usually remove the bolt that holds together the fuel bowl. You can remove it with your wrench. Next, take the bowl out of its carburetor.
Next, use a screwdriver for removing the center bolt from your carb. This screw is located between the fuel float opening and the carb’s center. You should remove the screw that holds your mower in place.
The final step is to inspect your jet. It is easiest to inspect the jet by holding it up to the sun.
To inspect the Carburetor Jet, you will need the following tools
What You Should Do If Your Mower Keeps Acting Like It’s Running Out of Gas
Hopefully, now that you’ve identified the causes of lawn mowers acting like they are running low on gas, you will be able to fix them. So, let’s take a look at what you can do to fix them.
Fixing the Gas Cap
If you have a pin, needle or a pin, you can clear out the vent with a gas caps. To poke the vent with a thin wire (such like a pin), you can use that wire to make it stick. This will clear any blockages. This is the most difficult part. It’s so simple that most people miss it.
Finally, if you think the fuel cap is damaged, you’ll want to replace it with a new one. If you are looking to buy a universal gas cap at your local hardware store, be careful. They may not all work with your mower.
Replacing the Fuel Lines
The diagnosis was half done. Now all you need to decide is whether you’re going to clean the old lines or replace your mower’s fuel lines with new ones.
If you have all the parts and time, I suggest that you just replace the lines. So, grab yourself some new fuel line, making sure that it’s the correct diameter, and cut it to length. Make sure it’s straightened so it fits snugly on your mower.
Take your time when cutting the new fuel line. If you cut too short, the line could bend. This will stop the flow. It is possible to end up stretching it, and it may not fit.
Change the fuel filter
So, to change the fuel filter, you’ll need a pair of pliers and a replacement filter. Start by removing the fuel lines clips from the end of the filter. Next, remove the fuel lines from the filter. This should be simple with a quick twist.
Next, place the new filter on the fuel line. The fuel lines can be twisted again to aid in the next step. Once the fuel line is reattached to the clip, you can reposition it with your pliers. If this is your first installation of a filter, it might not be obvious that each filter has its own orientation. Fuel can only flow in one direction. Check your filter for an arrow indicating which direction it should flow.
Change the fuel pump
It is easy to replace a fuel pump. To replace the fuel pump, you will need a pair pliers and a socket wrench.
With a pair of pliers, you will need to remove the connector hose clips. Next, pull the fuel line out of your fuel filter using the same motion as when twisting the hoses. Next, use a socket to remove the bolt that connects the pump to the engine.
Once you remove these bolts, you’ll be able to remove the old pump from the engine. Next, attach the new pump to the engine and take out the bolts. Attach the hoses and ensure they are in the exact same order as before. Finally, reposition all clamps.
Carburetor Jet Cleaning
If you have found that your mower has an obstructed carburetor jet, then you’ll want to use a tool small enough to clear it. This can be done with a small metal file or a pin tool. The key is to make sure you don’t damage the jet inside and that the opening doesn’t get any larger.
Once the blockage has been removed, reinstall it in the carburetor. Replace the screw that holds in the fuel bowl. Next, attach your fuel bowl to the carburetor.
