Some Common Small Engine Problems (and How To Fix Them)

August 4, 2022

Small engines that power equipment like lawn mowers are pretty straightforward. They are not as complicated as those found in modern cars. Still, you may slowly or suddenly encounter problems here and there after using them for a while. 

While many think they will need a trip to the mechanic to get their machines repaired, some small engine problems can actually be sorted out at home. We have rounded up some of the common issues you may encounter and how to fix them on your own.

Engine Won’t Start

When an engine has difficulty starting or won’t start at all, it may be due to any or all of the following reasons:

  • Stale or Dirty Fuel

If you think the gasoline has been sitting in the machine for too long (three to six months), it probably has gone stale already. Drain the old fuel immediately to a separate container and fill up your equipment with fresh gas. The same goes for dirty fuel.

  • Dirty or Clogged Carburetor 

The carburetor supplies air/fuel mixture to your engine. If it is dirty or clogged, the required air and fuel combination cannot travel smoothly towards the engine. Get a carb cleaner spray (from a hardware or auto supply store) and follow the instructions on how to use it.

  • Bad Spark Plug 

Remove the spark plug to inspect its appearance and the gap between the center and ground electrodes. If the gap has become wider than the manufacturer’s recommendation, bend the ground electrode to bring it closer to the center one.

If the plug is dirty, use a wire brush to scrape off deposits from the electrodes. It is advisable to replace the spark plug every season or 25 hours of use for optimal performance.

It Starts but Suddenly Stalls

As with startup failures, check the spark plug, carburetor, and fuel quality. In addition, see if the vent in the fuel cap is unobstructed. Clean it with a dry cloth or paintbrush if it is clogged by dirt and grime. If the cap is too dirty or damaged, you will need to replace it.

Power Loss

The air filter may be clogged if the engine doesn’t seem as powerful as it used to be. Remove the air filter to see whether it needs cleaning or replacement. 

You should also check the engine oil. If it’s already too dark and dirty, you need to change it immediately.


Overheating in the engine can happen as a result of lower oil levels. Top up the oil or change it. If the cooling fins are dirty or clogged, clean them as well.

These common small engine problems can be easy and inexpensive to DIY. If the issues persist after performing the steps suggested, contact Eagan Hardware Hank in Eagan, MN. Our technicians will gladly do the small engine troubleshooting for you.