Outdoor Power Equipment, Small Engine, Lawn Mower Repairs, Troubleshooting and Safety

Mark the positions of the throttle and choke cables and disconnect them (#1).

After removing the air filter, rotating screen and blower housing, disconnect the engine crankcase breather tube (#2, red) from the air intake horn (#2, blue). Gases that blow by the piston rings and valve guides into the crankcase pass through a flapper valve (the breather) to the air intake to reduce pollution.

Disconnect the wires (#3, red) that feed the anti-afterfire solenoid (#3, blue) mounted on the carburetor fuel bowl. When the engine is shut down the spark is disabled and the engine coasts to a stop. While the engine is coasting, fuel is still being drawn in from the carb, and the unburned fuel continues out to the hot muffler where it may explode loudly. The anti-afterfire solenoid stops fuel flow into the engine as soon as the keyswitch is turned off. The plunger or pintle is extended at rest and retracts when supplied with 12 volts.

The solenoid may also be mounted at the bottom of the fuel bowl (#4).

Disconnect the fuel line at the carb (#5, blue).

Remove the intake manifold screws and remove the air horn, carb and manifold as an assembly (#6) while disconnecting the governor / throttle link from the governor lever. Engines with aluminum intake manifolds may have a spacer (#5, yellow) whereas those with plastic manifolds do not.

The governor to throttle link is assembled to the throttle lever from the from the inside out as shown (#7).

Remove the four studs that hold the carb to the manifold. Disconnect the choke link when separating the carb from the manifold. The link is assembled to the choke lever from the outside in (#8).

When the keyswitch is off the anti-afterfire solenoid plunger (#9, blue) blocks fuel in the bowl from flowing into the center tower (#9, green). An o-ring (#9, red) seals the passage to the emulsion body.

With the fuel bowl (a.k.a. float bowl) removed, the float, emulsion tube body, main jets and bowl gasket are visible (#10) in this view from below.

With the carb upside down the float should sit parallel to the carb body. Grasp the flatted end of the float hinge rod with needle-nose pliers. Rotate the rod back and forth while pulling outward to remove the rod, float and inlet needle (#11).

When the float is lifted out, the inlet needle will come out with it. It is assembled as shown (#12). Inspect the needle's rubber tip for wear, corrosion or damage. Shake the float to see if fuel has leaked into it.

Check the inlet seat for debris or corrosion (#13). It is not replaceable.

Fuel from the center tower of the fuel bowl (#9, green) continues through the main jets into the emulsion tube body. The bowl gasket must form a good seal between the fuel bowl and carb body (#14).

The main jet can be removed by pushing it out from the opposite end of the emulsion tube body (#15).

An o-ring seals the main jet and emulsion tube body (#16).