Does the spacing on the coil matter that much?

Discussion in 'Mechanic and Repair' started by DFW Area Landscaper, May 28, 2006.

  1. DFW Area Landscaper

    DFW Area Landscaper LawnSite Silver Member
    from DFW, TX
    Posts: 2,116

    My Stihl line trimmer, FS80, started getting to where it wouldn't start. So I test the compression. It is holding 110 psi, which tells me the engine is good.

    Last time I encountered this problem, on my FC75, I bought a new plug, coil & carb and it ran like new. It cost me about $100 for parts all together, but I've got a like-new edger for back-up.

    So I figured I would do the same with the FS80. It was getting to where it just wouldn't run, so I replaced the plug, coil & carb and it started right up. Ran fine. Gave it to one of my crew leaders so he could test it in the field. He comes back in and tells me it ran fine for about 4 or 5 lawns and then it was very hard to start so he went back to his regular line trimmer.

    I tried to start it cold when he turned it in. It started fine and ran fine. Got it warm. Killed the engine and it restarted with a single pull and ran beautifully.

    The next day, I tried to start it again and it was like a different machine. It sputtered and if I moved the lever away from choke, it would die. So I gave up. Came back a few hours later after it had completely cooled down and pulled the rope again. It ran beautifully, once again. Got it warmed up, killed the engine. It re-started fine. But then I tried it agian, cold, the next day and it was sputtering and wouldn't run.

    Over the course of the next two weeks or so, I went through this scenario several times.

    I took it to the dealer and asked them to fix it. They say it's fixed and I will pick it up this week.

    Is the gap between the magnetic whatchamacallit and the coil that important? Could that be the problem?

    Later,
    DFW Area Landscaper
     
  2. Mark McC

    Mark McC LawnSite Bronze Member
    Posts: 1,565

    I guess it could, but let me ask you this: as the owner of a business, aren't there more profitable ways to spend your time than rehabilitating equipment?
     
  3. topsites

    topsites LawnSite Fanatic
    Posts: 21,653

    Why does America continue on its path of waste?

    We're talking 300 dollar weedeaters that take 1-2 hours to stick a coil, carb, plug and filter on. But, if you'd rather spend the 300 and throw the old one away... No wait, keep it for parts, right? If so, why? Why keep it for parts?

    Only thing I wish I knew, where are all these decrepit weedeaters?
    I'll buy every last non-working weedeater for 50 dollars a piece all day long.
     
  4. Dashunde

    Dashunde LawnSite Senior Member
    Posts: 628

    Clogged fuel system?

    It either has a good spark or it does not.
    The only exception being that they can fail due to a bad coil or other parts when heated up.
    But your problem is relative to starting and shows itself even when its cold... So its not ignition.

    Have the carb totally rebuilt, tank and lines flushed out, filters replaced.
     
  5. lawnboy dan

    lawnboy dan LawnSite Gold Member
    Posts: 3,712

    sthil of this vintage are famous for coil problems. its the reason i gave up on them. that and the crappy troudle prone zama carbs they use
     
  6. grassmanvt

    grassmanvt LawnSite Senior Member
    Posts: 906

    Than have I got a deal for you. I bet I've got a half dozen or so. A couple are completly dead but a few will porbably be resurected with parts from one another to make spare equipment. My thinking is the opposite of yours. If its crunch time and a wacker dies, if its older than two years old, it gets replaced and I deal with it later when I'm not so busy. I can't afford to have down equipment and if I've gotten a couple years out of a $300 wacker, if anything even close to major fails, it becomes a parts machine or sent to auction. When you figure out how cheap per hour used they are it makes good sense to me.
     
  7. topsites

    topsites LawnSite Fanatic
    Posts: 21,653

    Well ok, to each their own I suppose. Worst thing would be shipping, thou I'd gladly pay for parts, I think I'll see about finding some local guys, now I'm fairly certain there must be other Lco's with your mentality and no offense but if two of us get together, we'd both have the best of both worlds.

    Right now I have the same problem with an Echo-srm260s, stutters and sputters until suddenly it runs great and strong. psi is 120, the muffler is off and I've scraped out the port, the only things left are carb and coil but to replace both with new is, as you say, not profitable (I don't entirely disagree, in parts purchased plus labor it is too expensive). But if I can find some used srm-260s of about the same year (yeah because they have minor changes) I think I'll be fine.

    Now with the auction... I have thought of donating mine to charity and deducting $100 for it from taxes.
     
  8. oldrustycars

    oldrustycars LawnSite Senior Member
    Posts: 301

    i just did a friends FS80. all new fuel lines fixed the problem. i did rebuild the carb, for good measure, so i cant say for certain it was the lines. the dealer i got the parts from said the lines are famous for going bad from fuel additives, and they get like overcooked spaghetti. these felt like it, im assuming they would suck closed. it would run on 99% choke. no problems reported to me in the 3 weeks since i gave it back.
    as far as the coil air gap, the Briggs web site says the gap on their engine cannot be too wide to work. if it was set as wide as it would go, the timing would be a tad late. but thats just briggs, not stihl.
    and DFW, good for you fixing this stuff. my friend has newer equipment, and keeps the older stuff for backup, or sometimes adds a crew in the busy times.
     
  9. AAELI

    AAELI LawnSite Senior Member
    Posts: 362

    Timing is a function related to the position of the placement of the rotor on the crankshaft, not the distance between the rotor and the coil. Gap distance does make a difference in the ease of starting. But as previously mentioned the problem seems to reside in the fuel system. Only other source for those symptoms could be crankshaft oil seals. They sometimes have a tendency to move or even deteriorate due to high heat from slow running trimmers. Slow running=less cooling by rotor/fan.
     
  10. DFW Area Landscaper

    DFW Area Landscaper LawnSite Silver Member
    from DFW, TX
    Posts: 2,116

    I guess I will replace the fuel lines and see if that fixes the problem.

    Thanks,
    DFW Area Landscaper
     

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