stihl cut off saw ts400 help

Discussion in 'Mechanic and Repair' started by motoraced, Nov 30, 2006.

  1. motoraced

    motoraced LawnSite Member
    from md
    Posts: 39

    my saw only runs wide open throttle....the second i let go of the throttle, it instantly goes dead...played with the screws and nothing. what gives?
     
  2. The Rookie

    The Rookie LawnSite Senior Member
    Posts: 296

    run both screws all the way in. then unscrew each one one full turn then try it. if it will not idle then you probably have internal carbureator problems and or internal engine problems.
     
  3. khouse

    khouse LawnSite Bronze Member
    Posts: 1,465

    clean carb,fuel cell, new fuel, new filters
     
  4. MowerMedic77

    MowerMedic77 LawnSite Bronze Member
    Posts: 1,164

    How old is the unit? And how is the maintenance I have seen lots of saws that have sucked way too much concrete dust in their life and then will not meter fuel properly.
     
  5. Godfather

    Godfather LawnSite Member
    Posts: 186

    possibly the kill switch, because it is a wire that goes right near the throttle line, inside of the handle.
     
  6. motoraced

    motoraced LawnSite Member
    from md
    Posts: 39

    it's less than a year old, but looks like it's 15....it is used quite a bit by my dumbass employees...lets just say i am replacing the starter cord weekly...i'm not joking, complete morons.

    anyways, i took the carb apart, cleaned it spotless. put it back together and it does the same thing..only works WOT. upon thinkin, i did notice the top diafram was stiff. probably not as flixible as it should be. could a hardened diafram cause it to work only WOT?
     
  7. motoraced

    motoraced LawnSite Member
    from md
    Posts: 39

    and it has new fuel and filters...
     
  8. MowerMedic77

    MowerMedic77 LawnSite Bronze Member
    Posts: 1,164

    Was concrete dust getting into the carb before the cleaning and new filters?
     
  9. motoraced

    motoraced LawnSite Member
    from md
    Posts: 39

    i sure hope not. i cleaned everything before the carb..all lines and suck..seemed to be working properly...even when i shot cleaner into the holes of everything, it all blew out. my only thought is the diaphragm, unless if could be something in the cylinder, but i would expect a change in exhaust, but no smoke or anything.
     
  10. pugs

    pugs LawnSite Gold Member
    Posts: 3,022

    Put a new carb on it.

    I have had them like that...you can rebuild and adjust adjust adjust...doesnt change anything. There is something internally wrong/damage that you probably cannot get to to fix.

    Put a carb on it, you will save time and headaches and have the machine running again.
     

Share This Page