How to Improve Performance on a 5HP Briggs & Stratton Engine

Turn off the engine and open the hood. Make sure the Briggs & Stratton engine's spark plug is securely connected. The spark plug is on the right side of the engine assembly and is a small, narrow piece connected to a thin, black ignition wire. Reconnect the ignition wire to the spark plug if it is not connected by sliding it back into the rear of the plug.

Replace the spark plug if the current plug shows visible wear or corrosion on the end and the engine is not starting. Disconnect the ignition wire and insert it into the rear of a new, replacement spark plug.

Check the carburetor if the engine runs but is "sputtering" and otherwise struggling to initially start. Begin by cranking the engine so that it starts. Note the sputtering noises.

Locate the carburetor bowl halfway down the right side of the engine. There is a small needle valve on the bottom of the bowl that acts as an air adjustment valve. Improper air intake into the engine will lead to sputtering. Tighten the needle valve as far as you can to the left, then turn it back slightly to the right.

Listen to the engine and check if the sputtering disappeared or improved at all after adjusting the needle valve. If sputtering continues, turn the valve to the right another quarter turn and listen for sputtering. Continue making slight adjustments back to the right on the valve until sputtering and engine "whining" ceases.

Turn the 5HP Briggs & Stratton engine off.

Position a pan under the bottom of the 5HP Briggs & Stratton engine's carburetor's bowl if engine sputtering and poor performance continued even after the needle valve adjustments. Loosen the nut on the underside of the bowl with a socket wrench. Wait as the gas leaks out into your pan.

Remove the nut from the carburetor and place it in a bowl of carburetor cleaning solution. Allow it to soak for several minutes.

Remove the now loose carburetor bowl from the engine and clean its inside out with a damp cloth.

Set the 5HP Briggs & Stratton engine's bowl back into place and tighten the nut back into the carburetor's bottom with your wrench. Cleaning of the carburetor in this fashion will improve performance.