The carburetor is responsible for sending the correct amount of fuel and air into the engine cylinder for combustion. As carburetors begin to age, the internal components may begin to wear; water and sediment works its way into the jets and needle causing the engine not to start, or the engine starts to surge so it is unable to perform at the optimal level. Having a basic knowledge of engine theory is required to repair a carburetor. This procedure will take 30 minutes to complete.
Set the engine on a hard, level surface. Locate the carburetor on the right side of the engine, directly under the air filter.
Twist off the screw that holds down the air filter cover; remove the cover, air filter, and air filter holder. Loosen the two bolts that hold the carburetor against the engine block. With a piece of paper and a pen, draw how the carburetor linkage is hooked up. Remove the two linkage rods by hand, do not bend the linkage rods or stretch the spring that goes over one the linkage rods.
Remove the two carburetor bolts. Flip the carburetor over; remove the bolt on the bottom of the carburetor that holds the bowl on with the wrench set. This will expose the carburetor float and inlet needle.
Remove the pin that holds the float in place with the needle-nose pliers. Slide the float off and set to the side. Remove the needle jet with the flathead screwdriver, under the jet is the rubber seat, remove the seat by using the flathead screwdriver to pull it out.
Slide the new seat into place with the flathead screwdriver. Tighten down the new needle with the flathead screwdriver. Reinstall the float with the needle-nose pliers and tighten down the carburetor bowl. Reattach the linkage by referring to the drawings made earlier. Tighten down the two carburetor bolts and reinstall air filter holder, air filter, and air filter cover.