Carburetor installation

With the carburetor positioned in its approximate location on the engine:

  • Reinstall the throttle and governor linkages Where there is no speed adjustment or idle position, the direct governor linkage goes in the hole closest to the engine and the spring hooks onto a fixed vertical metal strip with only one hole at one end and the lower hole in the governor lever at the other. Thus, in operation, the spring attempts to keep the throttle open and the governor pulls on the throttle to close it. Increased spring tension results in higher speed. Don't get these backwards when you go to reinstall the carburetor on the engine!!! See the section: Throttle/speed control linkages on Craftsman/Tecumseh engines.

  • Reattach the primer tube, if any.

  • Reattach the stop switch wire, if any.

  • Install the carburetor onto the engine with a new gasket if needed. Tighten securely (6 to 8 ft-lbs).

  • Double-check that the throttle linkage and governor spring are in the proper holes and nothing is binding - you should be able to move the throttle back and forth without any sticking or tightness. It should return to the full counterclockwise position instantly as a result of the governor spring tension.

  • Do not replace the air filter at this time.

  • Reinstall any throttle selector or cable. Confirm that it operates properly - usually STOP, LOW, HIGH. STOP should engage the stop switch. LOW should leave the governor spring tension where it was. HIGH should increase the governor spring tension slightly. If there is an IDLE position, the throttle plate should be almost closed.

  • Reinstall any trim pieces that were removed.

  • Reinstall the fuel tank and fuel hose with clamp, if any. Open the fuel valve, if any.
  •  

Throttle/speed control linkages on Craftsman/Tecumseh engines

 

The following is for one model! NOT ALL ENGINES ARE SET UP THE SAME! It is best to consult your engine manual. Getting it wrong is not something you really want to do! :(

The user speed control (if any) pulls on a spring which is attached to the 2nd hole from the top on the governor lever. For engines with no speed control, there is a fixed plate or tang to which the spring is attached. Some amount of adjustment is possible by bending this plate.

The carburetor throttle plate has several holes in it. The one that is probably used is that closest to the little cutout (which I can't show with ASCII art) and the tip of the throttle plate return spring. You can probably confirm this by looking for which hole has the paint worn off!

                 
                     __                              _
          Open <-- /    \ --> Close                 | |
                  |o=========.               ,=======o| Top hole
                   \ O   /    '============='       | |
                     \_/ Carburetor   +-- ===========o| Next hole
             _           Throttle     |             | |
            |o|          Plate        +-straight-+  | |
            | |                                  |  | |
            |o=====o---/\/\/\/\/\/o========== ---+  | |
            | |           Spring                    | |
           | O |                                    | |
         Speed Control                              | |
         or Fixed Tang                    Governor  |_|
        (linkages may cross)                 Lever | O |
                                                   +---+

See: Neil's Tecumseh Throttle and Carburetor Linkage Page for some slightly better diagrams. :)