How to prime a lawnmower carburetor

Starting a cold lawnmower engine requires that you prime the carburettor. When a lawnmower sits for a period of time, the fuel in the carburettor evaporates. Priming is a way of putting some gas into the carburettor float bowl to start the lawnmower engine. Most lawnmowers have a soft plastic or rubber bulb to push gasoline into the carburettor. Priming a lawnmower carburettor is pretty much the same process no matter who manufactured the mower.

Remove the cap from the lawnmower fuel tank. Fill the tank with gasoline and replace the cap.

Locate the primer bulb on the side of the lawnmower engine. The primer bulb is usually red and located under the carburettor.

Press and release the primer bulb three times with your finger to prime the lawnmower carburettor.

Pull the throttle lever on the lawnmower handle to the "fast" position.

Grab the pull rope with one hand and pull it slowly until you feel resistance. Hold the throttle bar against the lawnmower handle with your other hand and pull sharply on the rope to start the engine.


Place the throttle lever between the "slow" and "fast" positions once the engine is running. It may take several attempts to start a cold engine. If the engine does not start after three pulls, reprime the carburettor.

Things You'll Need

  • Gasoline
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About the Author

Kenneth Crawford is a freelance writer with more than 10 years of experience. His work has appeared in both print and online publications, including "The American Chronicle." Crawford holds an associate degree in business administration from Commonwealth College.