How to replace the coil?

Discussion in 'Mechanic and Repair' started by CSRA Landscaping, May 18, 2002.

  1. CSRA Landscaping

    CSRA Landscaping LawnSite Bronze Member
    Posts: 1,232

    I've been told that the coil on my Stihl FS85T is prob. going bad and since I cleaned the carb and that didn't do it, or the carb screw adjustment, my guess is the coil. Here's the question:

    How hard is it and how much does it cost to replace the coil on the trimmer?
     
  2. khouse

    khouse LawnSite Bronze Member
    Posts: 1,465

    what's it doing?
     
  3. CSRA Landscaping

    CSRA Landscaping LawnSite Bronze Member
    Posts: 1,232

    First, the primer pump isn't working at all anymore, seemingly, since no gas comes into it when I prime it.

    I have to start it with the choke on all the time, not just when cold. And then it gets real, real hot while it's running.

    Give it the gas quick (normal) and it dies. I have to 'feather' it up to full throttle.

    Finally, slack off the gas while it's running and let it idle for longer than 4-5 seconds and it will die and good luck getting it started under a minute.

    As you can imagine, this is beginning to get a tad bit old.
     
  4. khouse

    khouse LawnSite Bronze Member
    Posts: 1,465

    Well that's not the coil. You need a major carb rebuild. I would check into a brand new carb as some of the prices are very reasonable compared to rebuilding them.
    It's running hot because it's running very lean. Maybe it's just a hose problem. Also check out the fuel filter thats attached to the fuel pick up hose inside the tank.
     
  5. CSRA Landscaping

    CSRA Landscaping LawnSite Bronze Member
    Posts: 1,232

    :rolleyes: Guess that shows what I know about it. The hoses are clean, the filter didn't seem to be the problem but I'm sure it won't hurt to replace it anyhow. The carb looked good, but then again, I wasn't sure what I was looking at, I just knew what the guy at the shop told me and that's what I did (cleaned the jet). I'll check into that, sine I'm sure it's a lot cheaper than a new trimmer. Thanks for your help khouse.
     
  6. thelawnguy

    thelawnguy LawnSite Silver Member
    Posts: 2,412

    The primer doesnt work because one of the two fuel lines is cut and its sucking air. Also why its running lean. I would suggest replacing the carb, fuel lines and tank grommet where the two lines enter the tank.
     
  7. CSRA Landscaping

    CSRA Landscaping LawnSite Bronze Member
    Posts: 1,232

    Ok, so couldn't I just replace the lines and the grommets or would this have messed up the carb too by now?
     
  8. khouse

    khouse LawnSite Bronze Member
    Posts: 1,465

    When in doubt do the cheapest first. Change the lines and filter and see. If that does't do it then do the carb. I think a brand new carb for that is $51.00. Make sure the fuel tank is good also.
     
  9. Fish

    Fish LawnSite Member
    Posts: 139

    Before spending money, you might want to remove
    the muffler and look at your piston and make sure
    there is no piston damage already.
    fish
     
  10. CSRA Landscaping

    CSRA Landscaping LawnSite Bronze Member
    Posts: 1,232

    Ok, I'll do that ... I've already taken the muffler off and looked at the piston, it's good.
     

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