How to Set the Throttle on a 16HP Riding Mower

Park the mower on a level surface in the lawn or on a driveway. Set the parking brake, leave the transmission in gear and turn the mower off.

Raise the hood of the mower to access the 16 hp engine. Remove the nut holding the air filter housing cover in place and set aside. Pull the housing cover and air filter from the air filter housing to access the carburetor and adjustment screws.

Turn the idle speed screw clockwise with a screwdriver until you see the needle on the end of the screw touch the seat. Turn the screw back counterclockwise 1 and 1/2 turns with the screwdriver.

Locate the main jet adjustment screw at the base of the carburetor. Turn the screw counterclockwise until you feel the needle on the end of the screw touch the seat in the carburetor. Turn the screw back clockwise 1 and 1/2 turns with the screwdriver.

Place the air filter back in the air filter housing. Shift the mower transmission to neutral, place the throttle in the neutral or middle position and start the mower. Allow the mower to idle and the engine to warm up for five minutes.

Turn the idle speed screw clockwise until the engine begins to stall, then counterclockwise until the engine begins to stall. Turn the screw back to the middle position where the engine idles smoothly.

Move the throttle to the idle position. Locate the throttle lever on the carburetor and hold it against the idle speed screw. Repeat the process of turning the idle speed screw counterclockwise until the engine begins to stall, then clockwise until the engine begins to stall. Return the idle speed screw to the middle position to obtain the true idle speed setting.

Secure the air filter cover back on the air filter housing for operation.