Rough Running Engine?

We have received many questions concerning rough running engines. There are a number of problems that could cause a snow blower engine to run rough. Some times some problems can be long term and can result in damage to the engine. Other times the issues could be a momentary glitch that can be fixed quickly.


Some reasons why a snow blower engine may run rough is due to:


  • A cycling engine
  • Sputtering engine
  • Wheezing and lagging engine


If the engine speed cycles up and down, it could be due to fuel flow. A number of things could be causing the problem. They could include:


  • Something in the gas tank. Something in the gas tank can restrict fuel flow and cause surges and stoppages of the flow of gasoline. Open the tank and shake out the blockage.
  • The carburetor is not feeding freely. Remove the plug from the bottom of the fuel bowl of the carburetor and see if the gasoline is flowing freely through the fuel system. If it isn’t, trace back through the fuel system until you find the problem.
  • Gummed up carburetor. If after troubleshooting the first two issues above and there is still a problem, take the carburetor apart and soak it in carburetor cleaner to remove build-up and then blow out all the orifices and jets.


The engine ignition could be causing the sputtering issue. To remedy this, check the spark plug to ensure that it is secure, clean, and gapped correctly. Measure the gap and adjust it in accordance to specifications.


A clogged air filter may be causing the wheezing and lagging. An air filter that has captured a lot of dirt and debris will restrict the airflow to the engine and this will cause the engine to choke up. Take a screwdriver and use it to remove the filter cover and then take out the old filter. If it is a foam filter, clean it with hot water and light detergent. Let it dry completely before reinstalling and running the blower. If the air filter is pleated, remove it and shake it out. If this doesn’t clear it of debris, then simply replace it.


We suggest that you repair the cause of a rough running engine on a snow blower as soon as possible. Other than performance problems, engine issues can also be a signal that the carburetor is deteriorating and that could result in an expensive rebuild.