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

Parts of the Tecumseh (Lauson) Series 3 Carburetor 632334a are highlighted in Photo 1 as follows: mounting bosses (yellow), idle well welch plug (black), external vent (red), idle speed screw (blue), primer tube fitting (pink), idle mixture screw (green), and main mixture screw (white).

The other side of the carb features the fuel inlet fitting (#2).

The float bowl (fuel bowl) should be installed with the step parallel to the float hinge and the deeper area away from the hinge (#3). The dimple on the deep end is there to help keep the float from sticking to the bottom.

This float bowl reads 'Lauson-Power Products Grafton, Wis. Made in USA' (#4). Tecumseh Products Company purchased the Lauson Company and their 4-cycle engine line in 1956 and Power Products who made 2-cycle engines in 1957.

The main jet includes the bowl nut and gasket, an o-ring and washer, and the needle screw and spring (#5). The spring keeps the needle screw from moving and keeps the o-ring tight against the nut. The o-ring seals the jet against fuel leakage, the washer protects the o-ring from damage by the spring and distributes the spring's force evenly on the o-ring.

The idle fuel transfer hole is drilled into the bowl nut in the area between the threaded portions (#6).

End view of the bowl nut with needle tip visible within seat area (#7).

The float is held to the carb body by the hinge rod (#8). A rubber bowl gasket prevents leakage of fuel and is important for the primer to work well.

With the carb inverted, the free end of the float should rest 11/64 inch from the body of the carb (#9). The float can be adjusted by bending the tab on which the float meets the inlet needle.

The float is removed from the body by sliding out the hinge rod (#10). When you lift the float from the body, the float needle (inlet needle) will come with it and may slide off. Be careful not to lose it.

The inlet needle is attached to the float by a clip (#11). When installed, the long end of the clip should point to the air intake or choke end of the carb.

A wire show the location of the external atmospheric vent (#12).

A ball plug seals the hole where the idle fuel pickup hole was drilled through to the inside of the center leg (#13).

A wire shows where inside the center leg, directly opposite the ball plug, is the idle fuel pickup hole (#14).

The scribe mark on the throttle plate should face outward and be in the 3 o'clock position for 8 thru 17 HP engines (#15).

Idle fuel orifices near the throttle closed position (#16).

Choke plate in the closed position (#17).

A view of the venturi with the choke removed (#18). The tip of the main nozzle is visible just beyond the narrowest part of the venturi.

The nozzle vent (air bleed) is located just before the venturi (#19). Air is drawn through this hole to mix with fuel rising up through the nozzle.

The throttle return spring is installed as shown (#20).