Briggs and Stratton have been making small engines for lawnmowers for over one hundred years. Whether its a small walk behind lawnmower or a riding lawnmower with a V-twin engine, the procedure for trouble shooting the carburettor can be implemented on any Briggs and Stratton small engines.
Park the lawnmower on level ground.
Remove the air filter cover located on top of the engine directly over the carburettor. Remove the air filter. Clean or replace the air filter.
Reinstall the air filter and air filter cover. Turn the engine over. If the engine doesn't start move on to the next step.
Drain the carburettor bowl. Directly under the carburettor is the bowl. On the outside of the bowl is a screw or bolt. Remove the screw or bolt and drain the gas out of the bowl. Check for sediment and water inside the bowl. Clean the inside of the bowl with a paper towel.
Reinstall carburettor bowl. Turn the engine over. If the mower doesn't start, continue to the next step.
Turn the adjustment screw all the way in and turn the screw back out 1 1/2 turns. The adjustment screw is located on the side of the carburettor. Turn the engine over. If it doesn't start, the carburettor needs replacement. To remove the carburettor, remove the two nuts on the front of the carburettor. Pull off the fuel line. Remove the throttle linkage from the side of the carburettor and slide the carburettor off of the engine block bolts. Remove both gaskets on each side of the carburettor. Install new gaskets on each side of the carburettor, slide back onto the engine bolts and reattach the throttle linkage. Connect the fuel line, and secure the new carburettor with the two nuts that where removed from the old carburettor.