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Stihl 088 Ignition Timing Issues

Discussion in 'Chainsaw' started by Mastermind, Mar 12, 2013.

  1. Mastermind

    Mastermind Work Saw Specialist

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    I've got an 088 that's freaking me out. The owner sent it to us because it was deemed "hard to start". Well now I build saws with well over 200psi on a regular basis.......so when the owner said he was having trouble starting it I just figured he wasn't putting his heart into it. :)

    Now lets talk about what we found on the saw.

    The piston was melted.......yep seriously.

    Not scored.......melted.

    [​IMG]

    Most of you guys have either met or seen pics of my son in law Jon. He's a pretty big guy......well starting this 088 scares him.

    I've been trying to find the ignition timing specs on the 088......but so far no luck.

    We set up a timing light on the saw and found that at idle its 47° BTDC. When revved it drops.......like I said this saw is freaking me out.

    We are setting up a 066 to check now..........
     
  2. josh1981

    josh1981 Addicted to ArboristSite

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    Looks bad. Good luck randy. 066 great saw
     
  3. Mastermind

    Mastermind Work Saw Specialist

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    The 066 is at 26-28°

    I'm gonna order a new coil for this 088.......hopefully Stihl will be interested in looking at it.
     
  4. Jacob J.

    Jacob J. Tree Freak

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    The rev-limited coil for these has been having real issues. There's a timing circuit in them and it can go bad, most likely the root of the cause on yours.
     
  5. Mastermind

    Mastermind Work Saw Specialist

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    Rev limited? See......now I'm gonna show my inexperience. I thought the 880 was rev limited but the 088 was not.
     
  6. o8f150

    o8f150 Tree Freak

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    see,, ole farts like us can learn:D:D
     
  7. Mastermind

    Mastermind Work Saw Specialist

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    Well Scott.......it seems like the more I find out......the less I know. :laugh:
     
  8. Jacob J.

    Jacob J. Tree Freak

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    If I'm remembering right, the 1309 coil is rev-limited. The 1308 coil is not rev-limited and is the desirable coil. The 880 uses a different ignition system.
     
  9. mweba

    mweba ArboristSite Sponsor

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    So what you're saying is, don't advance them to 47 degree? :msp_biggrin:
     
  10. showrguy

    showrguy Addicted to ArboristSite

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    randy,
    from what i remember some of the 088's (later versions) were limited as well as all the 880's..

    i have the limited coil you took off of my 880, i could send it for you to try ??
    or bring it along to bumpass in a few weeks.. if that helps..
    chuck
     
  11. UK Rich

    UK Rich ArboristSite Operative

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    Pah, that aint melted!

    [​IMG]
     
  12. Mastermind

    Mastermind Work Saw Specialist

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    Thanks for the offer Chuck. I'll order a new one. Hopefully I can have this saw back to the customer before then.
     
  13. DSS

    DSS uneducated rif raf and lovin it

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    It freaks me out that it would even start with circa 20* too much advance. Even with Jon pulling the string.
     
  14. Saw Dr.

    Saw Dr. Junk Collector

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    Stihl is soon to release an ignition module test box. Said to be able to test any Stihl module within the last 10 years or so, possibly more. If nothing else, save the module for future testing. They may very well take interest in this at the factory.
     
  15. young

    young token asian

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    yea the new efi tester doubles as an ignition tester.
     
  16. LegDeLimber

    LegDeLimber Addicted to ArboristSite

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    The rev limited stuff has had me hoping someone
    would stick a dual trace o'scope on the trigger and also on the output.
    Take a look at what was happening to the signals as revs climb.

    never heard if the limiter was a simple bandpass thing like
    the crossover in a speaker.
    i.e. it just begins to bleed off the spark~trigger signal
    at an approximate rpm/frequency

    or as trigger voltage climbs (from rpm) that gets it shunted off.

    or if it's something more of an active circuit.
    an active circuit would need a couple pulls of the recoil/passes of the magnets to charge/initialize and operate.

    Do the rev limited ones tend to take a couple extra pulls if they've
    been sitting for more than , oh say a few mins~to an hour?

    any ESD precautions listed for handling the parts?
     
  17. mweba

    mweba ArboristSite Sponsor

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    I just assumed there was a mouse running around in the flywheel making the spark speed up. Man I have no clue :msp_confused:
     
  18. Mastermind

    Mastermind Work Saw Specialist

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    What? Now you're saying that ain't how it works? :msp_mellow:




    I'm so confused.
     
  19. cpr

    cpr Addicted to ArboristSite

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    The last 2 months, I've had an irrational (yes, more than normal for what I build) need to have an 084 because I read how it wasn't limited like the 088s, yada...

    I think I'm good now.

    or better anyway...

    Oh, nevermind!
     
  20. blsnelling

    blsnelling Site Sponsor

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    You're not alone Randy.
     

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