18 Horse Briggs missing badly

Discussion in 'Mechanic and Repair' started by Dirty Water, Jul 16, 2006.

  1. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,794

    Like the subject says, my sister in laws craftsman mower is missfiring badly.

    Common problem? Easy fix?
     
  2. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022

    Is it a single or twin ? Model numbers tell all Jon.
     
  3. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,794

    Single, sorry...its not my mower, and I'm not around it.
     
  4. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022

    Well, If you had a in-line spark tester that would tell you if it was ignition or a mechanical problem. It could be ignition, carburetor, valves or even the flywheel key. Will it smooth out if the choke is applied slowly ? That would mean carb. problems.
    You can go to post 3 in this thread for proper valve adjustment if you want to check that; http://www.lawnsite.com/showthread.php?t=147559

    Do some checking and see what you can find.
     
  5. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,794

    It does smooth down with the choke partially applied. My thought on that was carb problem's too.

    I don't know much about small engine carbs though, I grew up wrenching on '80s EFI cars.
     
  6. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022

    There is nothing to these little carbs., Here is the break-down for both. Either one could be on that engine.

    See Ya
     
  7. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022

    The first pic. was blurred from my accelerator, Here's another try.....

    Carb..jpg
     
  8. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,794

    What do you think the issue is if its smoothing out when the choke is applied?

    As in, what should I look for if I dismantle the carb?
     
  9. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022

    Trash in the main jet (where the bowl nut screws in on the Walbro) the same area on the Nikki. But you want to shoot carb.& choke cleaner thru ALL holes and passages followed by compressed air while you have it apart. Check fuel tank for trash and clean if needed then replace the fuel filter and flush fuel lines for a proper job.
     

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