Home Forums Briggs & Stratton 4-Cycle Racing Briggs LO206 Engine running lean

This topic contains 3 replies, has 3 voices, and was last updated by  Clark Gaynor Sr. 2 weeks, 5 days ago.

Viewing 4 posts - 1 through 4 (of 4 total)
  • Author
    Posts
  • #84526

    William Weiler
    Participant

    I looked at my plug a month ago and it was grey/white so I put the carb needle up a notch to raise the needle. Then I took apart the carb and sprayed it out and got the part numbers on the jets and confirmed it was stock. Last weekend after running I checked the plug and it was bone white, way too lean. I raised the needle more. The engine also did this weird thing where when I started it full choke, if I lowered the choke bar, the idle went way up. When it was hot this problem went away and it seemed normal. The engine is used but I don’t want to blow it up. Can anyone diagnose what’s wrong? The temperature last weekend was in the 90’s, but shouldn’t that richen it up?

    TonyKart 401s LO206
    Masters Class
    Morgan Hill, CA

    #84527

    FREDDY SANDOVAL
    Participant

    You can’r read the spark plug like on a 2 stroke and expect it to be brown or darker. these motors are just like a car motor.

    The idle issue you may be having is most likely a vaccumm leak at the intake manifold or gasket, the engine cannot breath anywhere else other than the air filter area (front of carburetor)

    Run that engine, let it idle on the stand, spray small amount of car/brake cleaner around the suspected air leak area, and see if anything changes after you spray.

    #86395

    William Weiler
    Participant

    When I raced at Dixon, I saw the rubber cover on the throttle cable at the top of the carb was cracked pretty bad, so I taped it up with electrical tape. Do you think air could enter the carb at this spot? That might explain the weird idling problems. I will see if it happens again with the rubber cover taped up.

    TonyKart 401s LO206
    Masters Class
    Morgan Hill, CA

    #86481

    Clark Gaynor Sr.
    Participant

    First, both of our 206’s idle high when we first start them.  But after a minute or so, they settle down and are fine.  I don’t know why, nor do I care.  I’m only concerned how they run on the track and hot.  My kart doesn’t like to idle at all, and I’m OK with that too.  Our ultra high tech automobiles don’t always behave properly when they’re first started.  Why would you expect a very inexpensive, low tech, industrial, rototiller motor to do better?

    The rubber boot thing is a none issue to the best of my knowledge.  It simply holds the outer throttle cable in the top of the carb.  We’ve run engines with and without them and I never gave it much thought.

    William, just relax and enjoy.

    Clark.

Viewing 4 posts - 1 through 4 (of 4 total)

You must be logged in to reply to this topic.

Karting's News and Information Leader ekartingnews | an HMG publication