Help with Tecumseh HS40 linkage setting

Discussion in 'Mechanic and Repair' started by Budgetguy, Jun 5, 2007.

  1. Budgetguy

    Budgetguy LawnSite Member
    Messages: 3


    I am a novice home repair guy. I had left gas in the carb and it gunked up. Cleaned and installed the rebuild parts and it now starts great. HOWEVER....

    I took the linkage on the HS40-55580K engine off and now it runs wide open. I need help placing the spring in the correct lever hole and the solid connector from the lever to the throttle. I have read numerous forums and websites but cannot find anything on accomplishing this for a HS40 tiller engine.

    Please help identify which holes to use in :
    1. Hole in the lever to connect the spring to
    2. Hole in the lever to connect the solid connector (from the throttle)
    3. Hole in the throttle to connect the solid connector (from the lever)
    4. How to position the govener clamp when tightening the lever (or proper steps to follow).

    Any help anyone can provide will be much appreciated... Thanks..:cry:
  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

  3. Budgetguy

    Budgetguy LawnSite Member
    Messages: 3

    Thanks for the manual; I actually already had downloaded one and used it to try to adjust the linkage. There are all kinds of holes in the linkage and I cannot identify which to hook everything up to ( i cannot tell by looking at scratches).

    Is there a standard setting for the hookups for this engine on a Troybuilt?:dizzy:
  4. pugs

    pugs LawnSite Gold Member
    Messages: 3,025

    LOL...good luck. Up at the Tecumseh school they told us dont bother calling them asking what hole to put stuff in because they dont keep records of that.

    Basically you need to make a drawing before taking it apart or you are SOL and get to guess.
  5. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    After looking at the parts diagram the pic below appears to be the same as your control assembly so I would hook it up as shown and see how it runs. If the RPM is too high back it down with the adjustment screw.


    This is in the manual also for the governor adjustment.

  6. Budgetguy

    Budgetguy LawnSite Member
    Messages: 3

    Thanks Rostrorob (and pugs). I had called Tecumseh and yes they told me they did not keep pictures. Your picture was very helpful - Thanks a bunch!

    Linkage connected as specified and High speed works well; however, when I throttle down to low speed the engine surges. Actually, I cannot reduce the throttle down to low (only halfway between high and low) until it dies.

    1. I adjusted the main fuel mixture and idle speed screws as specified in the repair manual (finger tight, back off 1 and 1/2 turn, rotate clockwise until surge - rotate counterclockwise until surge - set halfway between each mark) prior to connecting linkage. This basically worked for main mixture.
    2. I connected the linkage and High speed works well
    3. When backing off using the handle throttle control I only get to halfway between High and Low and engine stutters, surges, and if I go any lower it dies. I try adjusting the idle speed screw with no success.

    Is there a specific procedure I should follow? Does the High Speed RPM screw and Idle crack screw come into play?
  7. Bill Kapaun

    Bill Kapaun LawnSite Senior Member
    Messages: 965

    Don't mean to step on any toes here-Rob is giving you excellent advice!
    "1. I adjusted the main fuel mixture and idle speed screws as specified....."
    I think you have idle speed and idle mix confused.
    The idle "crack" screw appears to be the idle "speed" screw.
    Screwing it in should raise the idle speed. However, it shouldn't be that much different then what it was before you started. You might turn it in "a bit" anyway.
    SURGING- could be caused by a couple different things
    1. Too lean. Do you have vacuum leaks? New gasket on the intake "joints" between carb & block? Bolts tight?
    2. I would think if the spring or linkage is attached to provide maximum "throw" on the throttle plate, the TP may react too quickly, instead of "easing" up/down.

    I've found that sometimes 1/2 way on the mix screws isn't the absolute best. I kind of prefer more of a 60/40 toward "out" (rich).
    I think the first thing I'd do (because it's simple) is turn the idle MIX screw out about a turn. IF things improve, it indicates vacuum leak. (You can set it back in then and fix the leak)
    BTW is there a LOT of slop in the throttle plate shaft? That can be a vacuum leak there.
  8. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    I though my shoes felt a little heavier this afternoon Bill.....JK

    Try and check as Bill mentioned.

    High/no idle could be caused by two things. It's possible there is still something plugging the idle circuit. You can drill a small hole in the center of reference #10 welch plug then carefully screw a sheet metal screw in just a couple threads then grab it with pliers and pull it out. Run a small wire through the holes behind this w/plug then spray/blow them out and install a new w/plug part # 630748.

    If after this and it still has a high idle, Mark the hole the spring is in now on the governor lever then move the spring DOWN a hole or two and see if you don't get a lower idle, This will most likely lower the high speed setting so you will need to adjust it back up with the adjuster on the control plate.


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