This troubleshooting guide is for when the lawnmower is started, runs for a few seconds and then cuts out. This is a pretty common problem which is usually one of just a few things that can be worked on to fix the problem.
WARNING!
Before starting any work on the mower, it is important to make sure that the spark plug boot is removed from the spark plug. This is to prevent any accidental start up and spinning of the blade. This boot simply pulls off from the spark plug and hangs to the side. Also, always keep hands and feet clear of the blade incase the blade starts to spin.
Also be sure to check that there is the proper amount of oil in the engine!!!
Tools required:
Philips Head Screwdriver
Flat Head Screwdriver
Pliers
Needle nosed pliers
Spark Plug Tester
1 can of carburetor cleaner
2 x channel lock / vice grip pliers
7/16″ wrench
3/8th inch drive Ratchet
¼” socket, 5/16″ socket, 3/8″ socket, 7/16″ socket, 1/2″ socket
The very first two things to check are the spark plug and the air filter. Using a spark plug tester place one end on the spark plug, and the other end in the spark plug boot. Pull the cord to turn the flywheel and watch to see if there is a bright orange light in the spark plug tester. If there isn’t, then replace the spark plug. To take the air filter cover off, remove the screws from the air filter cover (there is usually only one screw at the top of the cover). If the air filter is fully clogged then replace and see if the mower runs.
If those two things do not work it may be because the lawnmower has been sitting for a long time and it may have bad gas in the gas tank. The gas will smell old and musty. To remove and drain the gas tank:
Removing of gas tank:
1. Shut off the fuel valve (if there is one)
2. Clamp the fuel line so that it will not leak and then remove both of the clamps on the end of the hose. One is at the base of the fuel tank, and the other at the end of the carburetor.
3. Take off any screws/bolts that are holding on the gas tank and it should pull right off.
4. Drain the gas into a container to be properly recycled.
5. Put gas tank back on machine and fill with gasoline. If replacing gas did not fix the problem than take the tank back off so it is out of the way.
If none of this has worked so far then it is time to take off the carburetor to clean it. Generally if there was bad gas in the gas tank, then there is also bad gas in the carburetor and this is a necessary step.
Removing of carburetor:
1. First take off the air filter cover (if not already removed). Also clamp and detach the fuel line from the carburetor.
2. Now remove the three screws (usually 5/16″ bolts) that hold the metal plate onto the face of the carburetor.
3. Next remove the two (usually 7/16″ bolts) on either side of the carburetor that connect to the intake manifold. Make sure not to rip or lose either of the gaskets on either face of the carburetor. If any of the gaskets are ripped or destroyed you will need to go to a local parts store to replace them.
4. Now that the carburetor is free from the engine you will notice two very thin metal wires attached to the carburetor by a pivoting metal plate. This linkage is very important to how the mower will run. Be very careful not to bend this linkage when removing. Be sure to mark each hole that the wires were going through for re-assembly later. To remove the linkage twist and turn the carburetor until the hooked ends on the wire come free from the holes they are in.
Cleaning of carburetor:
1. First remove the ½” nut on the bottom of the carburetor on the “bowl.” There is also a small gasket over the threads of this bolt, do not lose this.
2. Now remove the float inside the carburetor. This has a needle balancing it with a small steel rod to hold it in place. Using pliers pull the steel rod out to one side. Now remove the float and needle. Place in a safe place where they will not get lost.
3. Now using the carburetor cleaner, spray the whole carburetor with the cleaner. Make sure to get the cleaner inside every hole in the carburetor. Also spray inside the holes that are in the ½” nut that was removed earlier on the bowl. The cleaner is removing any dirt contaminants and bad gas that may be inside the channels of the carburetor. If there is a lot of residue inside the carburetor it may be a good idea to take a small wire brush to remove this and then spray the carburetor again.
4. After thoroughly cleaning, it is time to put the float back in. Place the needle in between the two prongs on the underside of the float. Balancing this carefully, place back in position and slide the steel rod through the holes to keep in place.
5. Now attach the bowl to the carburetor using the ½” bolt. Turn until snug but do not over tighten.
Now attach the carburetor back to the engine in the reverse process of removing it. Make sure that the linkage is reconnected to the carburetor, the gas line is reconnected, fuel valve is turned back on (if applicable), the air filter is on, and the spark plug is connected. Now start the mower and see if it stays running.
If none of this fixed the problem then it is time to take the mower to a professional shop to be looked at. There could be something internally wrong with the engine itself, or it might have just not been cleaned well enough.
