Echo Trimmer Hesitation-Model SRM-1501

Discussion in 'Mechanic and Repair' started by jud149, Apr 21, 2005.

  1. jud149

    jud149 LawnSite Member
    Posts: 102

    When going from idle to wide open throtle, there is a noticable hesitation before full RPM's are obtained. Adjusting the carb will lessen this hesitation somewhat, but in doing so the wide open RPM's decrease. Any ideas would be appreciated.
     
  2. Tech man

    Tech man LawnSite Member
    Posts: 55

    Is this when it is still cold and warming up or after being run for a while? How old is the unit?
     
  3. jud149

    jud149 LawnSite Member
    Posts: 102

    This occurs after the unit has been warmed up. Its age is approximately 15 years old and has been used perhaps an average of 1/2 hour per week during its life.
     
  4. bligh61

    bligh61 LawnSite Member
    Posts: 240

    take apart muffler and clean out ports of carbon build up
     
  5. jud149

    jud149 LawnSite Member
    Posts: 102

    I followed your suggestion but it didn't help. Thanks anyway. What does affect this hesitation is the high speed adjustment screw. The more rpm's at wide open throtle I can achieve, the greater the hesitation. If I go a little more, it will stall when quickly opening the throtle from idle. The more I back if off, the less hesitation. Perhaps I'm adjusting it wrong in that I am looking for max rpm's.
     
  6. Tech man

    Tech man LawnSite Member
    Posts: 55

    Sound like you have a blown crankshaft seal or a blown cylider gasket. The unit needs to be sealed so air cant get into the engine from anywhere but the carb and when you turn the screw out your feeding it more gas which compansates for the air getting in. 15 years old, mabey its time for a new one?
     
  7. jud149

    jud149 LawnSite Member
    Posts: 102

    Don't think it's time for a new one. Other than the hesitation, it still runs like new. I did use it today for a while and it seems that the hesitation comes primarily after it idles 10 seconds or so. If you keep moving the throtle, the hesitation is hardly apparent. By the way, do you know what four-stroking means? The carb adjustment procedure states to turn the high speed screw until the engine runs smoothly without four-stroking under load.
     
  8. mike76

    mike76 LawnSite Member
    Posts: 27

    Sound like diphram in the carb is gitting stiff, or the fuel screen is spopped or dirty. Take the carb apart, the gaskets should bbe flexable like cloth. Check to see if the fuel likes are hard or the filter in the tank is dirty, try these and let us know how it goes.
     

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