Stihl 420C SEIZED UP!

Discussion in 'Mechanic and Repair' started by proenterprises, Nov 12, 2005.

  1. proenterprises

    proenterprises LawnSite Silver Member
    Posts: 2,297

    My stihl br 420c magnum seized up today. Since one of the guys was running it, I dont have much to go on. I sensed that their was a little too much oil in the mix of this batch, and it was a different brand than the 2 cycle that I normally use (just had a bottle and wanted to get rid of it)

    All I know is it stopped, and the starter rope is frozen. I dont have any idea how to fix, will probably bring it to the dealer Monday and get the bad news:realmad:

    Anyone have insight?
  2. befnme

    befnme LawnSite Bronze Member
    Posts: 1,413

    too much oil wont make it seize up , only the lack of oil will .
  3. geogunn

    geogunn LawnSite Gold Member
    from TN
    Posts: 3,010

    agreed--that is if it is an oil related problem.

  4. rodfather

    rodfather LawnSite Fanatic
    Posts: 9,501

    Probably a godsend you can get rid of that toy and get a Stihl 600 or an Redamx 8000 and make some real $$$ IMO:D
  5. befnme

    befnme LawnSite Bronze Member
    Posts: 1,413

    the stihl 600 has i beleive 3 recalls on it , one is that the fan will break apart and possibly come out of the housing . just be careful with it . also while thinking about it , maybe a piston ring broke and got caught between the cylinder wall and piston .
  6. rodfather

    rodfather LawnSite Fanatic
    Posts: 9,501

    We've had to have 3 of or 4 8000's fixed with broken choke levers. They break and then close shutting the unit down.
  7. Envy Lawn Service

    Envy Lawn Service LawnSite Fanatic
    Posts: 11,062

    How old is it?

    I'm guessing an air leak type seizure... as air leaking in can lean out the mixture.
    Old age, air leak or that's really some crappy oil.
  8. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    You can remove the muffler and look into the exhaust port with a flash light and tell if the cylinder or piston is scoured, This will tell you if it is blown or something else happened.
  9. lawnmaniac883

    lawnmaniac883 LawnSite Silver Member
    Posts: 2,613

    Pull off the spark plug, put some PB blaster or some light weight engine oil, take a screwdriver, put in hole, tap with a hammer, this MAY unseize the unit.
  10. proenterprises

    proenterprises LawnSite Silver Member
    Posts: 2,297

    Well, Im sure some would say it was "crappy" oil. I had a bottle of that Supertech 2000 (walmart) around, and Just wanted to get rid of it. However, it has seen ECHO brand oil for every tank until now (last 3 years). I cant imagine that one time would kill an engine. ;)

    Im just going to take it to my dealer on Monday. I do have to say, Stihl has really let me down on this one. I have never been happy with this unit, but when I bought it, I didnt know half of what I do now.

    Anyone else had this problem/>?

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