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echo pb 603

Discussion in 'Mechanic and Repair' started by aclassic, Apr 12, 2005.

  1. aclassic

    aclassic LawnSite Member
    Posts: 181

    i have an echo pb 603 blower and it wont run at low rpm's so i always have to rev it up and run it at high rpms (not a problem, i can probly adjust the carb) but after running for 20 min or so, the throttle jumps around, all of a sudden it goes low throttle and then works back up to high, it continues to do this until it can barely even run at high rpms anymore,
    is this an overheating problem? or what else could it be, i've already replaced the air filter, cleaned the carb and changed the plug. maybe the carb adjustment will help, but just let me know what you think
     
  2. KathysLGC

    KathysLGC LawnSite Bronze Member
    Posts: 1,345

    Did this happen all of a sudden or has this been an on going problem? Did you adjust any of the nedles in the carb?
     
  3. aclassic

    aclassic LawnSite Member
    Posts: 181

    i got the thing used for $50, replaced some stuff and it runs fine. i've taken it out a couple times and it did this both times. and no i havent adjusted the needles yet, would that really fix the fluctuation of rpm problem? it runs fine for 20 min or so, this is why i think it might be a overheating problem, but after i bought it i cleaned it up, i think i even took out the spark arrestor too.
     
  4. KathysLGC

    KathysLGC LawnSite Bronze Member
    Posts: 1,345

    Sounds like it could be a carb problem. Seems many people are having carb problems lately. :) Rebuild the carb and replace the needles. The kit will be under $10. so if it still doesn't work it's not big money lost. The float could be sticking. Yes carb problems can act up after the engine has warmed up. I fixed a unit that would run for about 10 minutes then the rpms would just go up and down. If I let the unit idle for a few seconds it would do it again after 10 minutes of use. it was a bad gasket in the carb. Once the carb had pressure it would do the rpm thing. I rebuilt the carb, adjusted the needles and I haven't heard of any problems with it yet.
     
  5. aclassic

    aclassic LawnSite Member
    Posts: 181

    sounds good,
    i'll start out by adjusting the needles, then go on to rebuild it if theres still problems.do you know what all comes in a rebuild kit?
     
  6. KathysLGC

    KathysLGC LawnSite Bronze Member
    Posts: 1,345

    Bunch of gaskets and rubber O rings. It should also come with a needle for the float.
     
  7. aclassic

    aclassic LawnSite Member
    Posts: 181

    i adjusted the needles so now it runs at low rpms w/out stalling (which is nice) but it still does the up & down thiing w/ rpms. looks like i have a carb to rebuild over the weekend, see how that works.
     

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