Tecumseh Carb

Discussion in 'Mechanic and Repair' started by Westbrooklawn, Nov 2, 2003.

  1. locutus

    locutus LawnSite Bronze Member
    from NC
    Posts: 1,266

    I was astonished to discover that Tecumseh makes the herolded peerless transmission. Is this the only decent thing they make?

    UNISCAPER LawnSite Bronze Member
    Posts: 1,426


    We had a 5 hp Techumseh that we put a forged billet rod in, shaved the head and took a smog pump and supercharged. It would run about 90 on a Bonanaza mini bike smoking clutches and peeling tires...
  3. JHC

    JHC LawnSite Member
    Posts: 42

    I have a 4hp Craftsman Edger. I rebuilt the carb but it will only run if you pump the primer on the carb. Then the exhaust glows red. Any idea what could be wrong? Does the bowl nut on the bottom need to be replaced?

    Also, I can buy a new "universal" carb on e-bay that supposedly fits all Techumseh 3 - 8 hp engines. The p/n is 640025 (I think) but my carb is 640172. WHould this "universal" carb work?
  4. SWD

    SWD LawnSite Senior Member
    Posts: 989

    Techumeh carbs have a soft foam white needle seat. The best way to remove them is with a small gauge piece of wire or with a sharp dental pick.
    What ever you do, don't soak these carbs in carb cleaner - use only non flammable solvent like safety solvent. The casting pores in the carb will expand and the carb won't work if you soak in carb cleaner.
    These T carbs are notorious for leaking like a pig due to this crappy needle seat design.
    When replacing, be very careful when seating the new seat and adjusting the height on the float. DO NOT press the float into the seat to get a proper float height as this will trash the seat and cause the fuel leaking out of the carb air intake.
    JHC, your problem is associated with a leaking needle seat as well. Your not flowing enough fuel to spill out of the carb intake, however, it is running rich enough to exit the exhaust port - also a common problem on these motors.
    Actually your problem is more severe as the excess fuel can 'whipe' the lubricating oil from the cylinder walls and cause premature wear in the cylinder and to the rings.
    As far as the universal carb, I am not familiar with it.
  5. SER

    SER LawnSite Member
    Posts: 60

    Try this. Remove the carb from the uit. Remove all loose items from the carb, ie needle and seat, float and pin, etc. Spray it down wiht gumout, or brake parts cleaner. MAKE SURE you get all the small orifices wet with the cleaner. Then take a piece of tag wire, similar to the wire used to tie closed a bread bag, and push it through ALL the orifices and openings inside the carb and the outside. Remember to get at the atmospheric vent openings. Then blow compressed air through all the openings. Replace the needle and seat, and bowl gasket. Replace carb. This should solve your problem. I HOPE.
  6. mobilefleet

    mobilefleet LawnSite Member
    from atl
    Posts: 17

    I have an easier fix. Replace unit with a Kawasaki powered or Honda powered unit. :D You will fight Teh-junk-seh all day getting it to start. Am I biased? You bet, cause I've worked on all these motors and know which ones last.
  7. mower_medic

    mower_medic LawnSite Member
    Posts: 77

    I rebuilt the carb but it will only run if you pump the primer on the carb. Then the exhaust glows red. Any idea what could be wrong?
    That red glow usually means the timing is off and your engine is running extremely HOT. Pull the flywheel off and check the flywheel key. Since you have the flywheel off, replace the key anyways since even the slightest shear will throw the timing off enough to make it run hot.

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