Stihl Edger Help

Discussion in 'Mechanic and Repair' started by morgaj1, May 12, 2012.

  1. morgaj1

    morgaj1 LawnSite Senior Member
    Posts: 318

    I have a Stihl FC75 stick edger that is 6-7 years old. It has a fair amount of usage, but it has always performed flawlessly. I noticed that it did not seem to have as much power the last couple of times I used it. This power loss is from start to finish, not just when it gets hot. Well, I put a new blade on it and the lack of power became readily apparent. I got out the tach and checked the carb settings. It was running rich, so I reset it to 10,000 rpm unloaded. After trying it again, it was a little better, but still lacking power. So, I checked the compression. With my Snap On gauge, it read 105-110lbs. This seemed low. For comparison, I checked the compression of my Husqvarna 326LS and Tanaka pole saw. They were 135-150lbs. Then, I pulled the plug and muffler and looked at the piston/cylinder. They look pristine. No scratches or anything. I cleaned the spark plug and threads and the plug seats fine. I also checked the muffler screen and it is clean. So, I am at a loss.

    1. What do you guys think is going on? Is this compression too low?
    2. I can get a new piston and rings for it, but I don't see how the cylinder comes off. It does not appear to unbolt from the top, like on a chainsaw. It looks like the bolts thread from the bottom, but I can't see the heads.
     
  2. morgaj1

    morgaj1 LawnSite Senior Member
    Posts: 318

    I thought about the clutch too. But, when under load, the rpm's drop significantly, to the point of stalling. So, I am confident that the clutch is hooking up appropriately.
     
  3. mjlcare2

    mjlcare2 LawnSite Member
    Posts: 200

    You can get a brand new one for as much as it might cost you to repair.. I might think that way instead
     
  4. morgaj1

    morgaj1 LawnSite Senior Member
    Posts: 318

    I am going to put a new set of rings in it myself. Should only cost $15-$20. If that doesn't get it, I will buy a replacement.
     
  5. herler

    herler LawnSite Fanatic
    Posts: 5,145

    It needs a new carburetor but if you buy a replacement let me know I'll buy it cheap!
     
  6. mjlcare2

    mjlcare2 LawnSite Member
    Posts: 200

    I know they make an aftermarket carb out there for around $40 ready to bolt and use for some of the late model years.. not worth the time and money to try and tool around to fix em.. that's just me
    Posted via Mobile Device
     
  7. morgaj1

    morgaj1 LawnSite Senior Member
    Posts: 318

    What's a carb going to do for lack of compression?:waving:
     
  8. mjlcare2

    mjlcare2 LawnSite Member
    Posts: 200

    Sounds like shade tree mechanics all around..
     
  9. herler

    herler LawnSite Fanatic
    Posts: 5,145

    Then why did you ask?
     
  10. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    Sounds like a bunch of know nothing parts changers around....
    Posted via Mobile Device
     

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