8HP Briggs not starting

Discussion in 'Mechanic and Repair' started by accurate machinery, Jan 28, 2013.

  1. accurate machinery

    accurate machinery LawnSite Member
    Posts: 165

    I am trying to fix a friends Craftsman snow blower, it is powered by a 8HP Briggs overhead valve engine, the stamped production is 010804, so it is a 2004 as I understand. It has a one speed carb, no throttle control, no points. Just a coil triggered by the flywheel. The machine runs good when it runs, but to start it, I have to hold the throttle closed with my hand while pulling the cord, and even then it only will start sometimes if I warm it up (bring it inside). The spark is pink and erratic not bright blue like I would like. I have cleaned the carb, it is getting fuel and has good compression, I think the coil is failing. Do these coils go bad? I am not use to replacing coils but I have been out of the repair business. Any help would be greatly appreciated! *trucewhiteflag*
     
  2. Patriot Services

    Patriot Services LawnSite Fanatic
    Posts: 12,450

    They do fail sometimes but try this first. Remove the coil and make sure all the mating surfaces are good and clean. Reinstall and set the correct gap (folded piece of paper works fine). See if that improves spark quality.
    Posted via Mobile Device
     
  3. Landrus2

    Landrus2 LawnSite Platinum Member
    Posts: 4,811

    Briggs and cold don't mix very well. First thing I would replace would be spark plug.
     
  4. accurate machinery

    accurate machinery LawnSite Member
    Posts: 165

    Sorry, I forgot to mention that I did replace the spark plug. I sanded the minor rust on the flywheel magnet. Thanks, Ken
     
  5. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Posts: 2,231

    Follow Patriot's instructions--what he means is to clean the coil and mounting bosses that the coil is mounted to, Over time corrosion develops and contibutes to a bad ground.

    In addition, you may try pulling the kill lead to the coil and check spark.
     
  6. Landrus2

    Landrus2 LawnSite Platinum Member
    Posts: 4,811

    OK we having some progress have you tested it for spark you say you have pink colored sparks that is due from 95 octane fuel no problem there.
    Do you have spark :waving:
     
  7. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    OK...I'll bite...
    Where does it say 95 octane caused or causes pink colored sparks...???:dizzy:
     
  8. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    My apologies in advance to the OP...again...
    I havent listed my certifications in over a week...this guy that has been a member of this site since 2006 must have forgotten...more than that I reckon...

    Kohler Certified Expert Tech since 1998...yes I have an update school next week..
    Briggs MST..Kawasaki Schools 98 to present...Hydrogear schools...Im sure Im leaving a few out..??
    In any case..I cant figure out how 95 octane...or anything to do with the fuel can affect the color of the spark...
    Im only familiar with yellow and blue sparks...we dont have pink sparks around here..
    Yellow is weak..Blue is good...Pink ??? the lighting must be playing tricks on his eyes.

    The 8hp Briggs in this thread has an inductive coil...clean the coil mounting areas and set the airgap to .010..with the kill wire disconnected...pull the rope...if you dont get a nice blue spark...coil is weak...
     
  9. accurate machinery

    accurate machinery LawnSite Member
    Posts: 165

    Thanks for the replies, I am guessing the owner has had this problem for a while, the electric starter is worn out and the pull rope is starting to frey. The gap on the coil has been set, the flywheel sanded and I have a weak looking spark. I know a spark should be bright blue, so I am suspect of the coil, since it seems at times to have no spark, wont start at all. Then with no reason it will start. That is what makes me suspect the coil, I am not used to replacing a coil and didn't want to go buy one to find out that it is not the problem, I also checked the flywheel key, it is normal. I know I have gas and compression, checked the valve clearances, all I have left is weak spark. :dizzy:
     
  10. Patriot Services

    Patriot Services LawnSite Fanatic
    Posts: 12,450

    You still need to sand the coil mounts, not just the flywheel.
    Posted via Mobile Device
     

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