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Thread: LO206 issues running on track

  1. #1

    LO206 issues running on track

    There is a racer running lo206 at our local track. He is running a purple slide in a sportsman class. He is having trouble with the kart missing and skipping when taking the turns, and on some rougher parts of the track. He reported it died completely one time. Any ideas on what to do? They changed the float level some, but have not changed anything else.

    This is our first year with the 206 motors at the track. I'd really like this class to take off and I think there are a lot of people waiting to see what happens with the first few guys that purchased these motors before buying in themselves.


    Edit: wrote plate instead of slide.

  2. #2
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    First thing to check is to make sure the kill switch wire from coil to switch is not being grounded by being pinched in sheet metal. Why are you running a plate? Different length slides work much better.

  3. #3
    Whoops, not a plate, a purple slide.

  4. #4
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    Make sure your fuel tank is vented. Do you have the carb and the valve cover vented to the same tank? If so, try removing the carb hose from the tank and just vent to the atmosphere as a test. Could still be a float issue and you also may need to raise the needle (drop the needle clip) in the slide. Just throwing out some common problems.

  5. #5
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    Check this out...had the same issue...if it's the same problem just read through the comments and see which solution fits your issue. Mine was that I had the pulse and carb drain line in the same catchcan.

    https://karting.4cycle.com/showthrea...quot-**VIDEO**

  6. #6
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    Because it is happening on in corners and on bumps, I would recommend checking the float height AND drop. In several cases, I have found the float drop on some new engines being so low it allows the needle to catch and therefore not shut off fuel to the float. This causes too much fuel in the float which can splash up in rough areas or in corners and cause the engine to flood out and die. If the float level itself is set to high, it can cause the same condition. Because of where this is happening, this would be the first thing I would check.

    The venting issue is real, however, it shouldn't be affected by roughness or g-forces in the corners, but rather cause the engine to die off after too much pressure has built up in the can from the valve breather causing the pressure to push up into the float and create a vapor lock. I would make sure the venting is adequate, and is an easy visual check, but I would go over the float before heading back out on the track.

  7. #7
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    Is your plug boot punched out?

  8. #8
    4 Cycle Advanced User Jimbo's Avatar
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    I see this quite often.
    Especially on the long slide motors. The longer the slide the more likely it is to happen.
    The longer the slide the less fuel you want in the float bowl.

  9. #9
    Thanks everyone for the help on this motor. I was able to spend some time with the racer last night and I think we have the kart running acceptably well. We haven't had it on the track yet, but if it stops raining we may be able to try this weekend.

    We started it up, after it had supposedly had 20 dyno runs by the engine builder/seller. The engine wouldn't idle. It would catch about half throttle and kind of run.

    This was the first time I had seen the kart in person and right away we noted the angle of the engine was wrong, and the carb was at a really excessive angle. I believe this is what caused most of the issue on the track. There was no way the float was moving freely. I think it bound up. The kart owner reported gas was running out of the carb after it died on the track.

    We changed the motor mount around, and used the slot in the intake pipe to level it as best we can.

    He does need to add a separate catch can for the carb. There was no overflow line on the carb at all.

    We checked all of your suggestions, working through each one. The float droop was excessive, it used the bowl as a stop. We adjusted the height of the float to the animal spec of .86 to start with.

    Ran the motor and it would now idle, but upon acceleration there was a large dead spot. It would sputter and then catch.

    We set the spark plug gap to .040. It ran significantly better, but still had the acceleration problem.

    Reset the idle mixture and speed per the book. The mixture screw was out 4-4.5 turns. It's now about 2 turns out. The engine ran better yet, not perfect.

    Then we started moving the needle. We ended up dropping the needle down all the way. It ran great, idles perfect no sputter, and accelerated great when we loaded it with the brake. We did another minor change to the idle screw and called it good enough.

    I'm excited to see how it does on the track. The builders keep on telling us it will not run well on a dirt track because of the rough surface, not sure I believe that.

    Thanks again for all the help. It's really appreciated.

  10. #10
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    If you have to run the needle all the way down, there is a problem some where. Have you had the carb completely apart? I would check for a drilled out main jet. Make certain the small brass fuel main tube above the emulsion tube is installed correctly and projecting up into the venturi. You should be able to see it looking into the carb, I have seen them left out and installed upside down.

  11. #11
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    Quote Originally Posted by mnkartracing View Post
    The builders keep on telling us it will not run well on a dirt track because of the rough surface, not sure I believe that.
    Never heard of that one before. We race them on dirt and have a hundred or more customers who race them on dirt each weekend. The class is really catching on here on midwest dirt tracks (finally.)
    These are evidently builders of engines other than the LO206, right?

    Also, what builder has time this time of year to dyno an engine 20 times (and why would he need to?) I've gotten requests to break in 206s for 12 hours before and had to tell people that I simply cannot afford to take that much time on the dyno...and then consider the cost to replace a load cell is around $1300... not exactly worth it to break in a 206 for that. I have since set up my old hydraulic dyno-saur for running these engines under load for prolonged amounts of time.

    I build engines for just about every class of karting, and as an engine builder, love the Lo206 package.
    Simplicity, durability, affordability, parity - what's not to like?

    Glad you got your problems ironed out.
    Sounds like your final tune is very similar to our bench settings for a purple slide 206, other than I have the needle up all the way and set the floats a good bit higher.



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    Thanks and God bless,
    Brian Carlson
    Carlson Racing Engines
    Vector Cutz
    www.CarlsonMotorsports.com
    28 years of service to the karting industry
    Linden, IN
    765-339-4407
    bcarlson@CarlsonMotorsports.com

  12. #12
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    Quote Originally Posted by Kart43 View Post
    If you have to run the needle all the way down, there is a problem some where. Have you had the carb completely apart? I would check for a drilled out main jet. Make certain the small brass fuel main tube above the emulsion tube is installed correctly and projecting up into the venturi. You should be able to see it looking into the carb, I have seen them left out and installed upside down.
    Yea, that's what I was thinking when I was typing my response about his carb tune.
    Question: You've said that you've found the main fuel nozzle installed upside down? Is that even possible? I would think that the e-tube wouldn't even catch threads that way.

  13. #13
    We kind of ran out of time to do anymore adjusting. Had to get my kids home and to bed. I think with a little more time we could've figured out why the needle had to be set down all the way.

    We may have some track politics going on with the engine guy. I'm not sure I've been told the entire truth.

    Thanks again for all the help.

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    Quote Originally Posted by mnkartracing View Post
    Ran the motor and it would now idle, but upon acceleration there was a large dead spot. It would sputter and then catch.
    Make sure to really clean the carb. The Needle Float Valve (#555648), I've had gunk get on the sidewall which wouldn't allow it to open/close properly and in turn will affect fuel levels no matter where your float is set to.

    Parts book: http://www.briggsandstratton.com/us/...ng/ms5701.ashx

  15. #15
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    May not have been upside down, it simply didnot project into the bore so may have been just not all the way in.
    Quote Originally Posted by CarlsonMotorsports View Post
    Yea, that's what I was thinking when I was typing my response about his carb tune.
    Question: You've said that you've found the main fuel nozzle installed upside down? Is that even possible? I would think that the e-tube wouldn't even catch threads that way.

  16. #16
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    Someone may have trimmed the nozzle down (not legal) and if it isn't protruding into the carb bore, it will not draw the fuel into the throttle body very well at low speeds.

  17. #17
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    Quote Originally Posted by jjchat View Post
    Someone may have trimmed the nozzle down (not legal) and if it isn't protruding into the carb bore, it will not draw the fuel into the throttle body very well at low speeds.
    You know that the WB3 has no nozzle at all. The KT 100 runs quite well with it.
    From the desk of Al Nunley 512-630-6215
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  18. #18
    4 Cycle Advanced User Jimbo's Avatar
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    How much fuel comes out of the discharge can depend on other things besides how much it protrudes into the air stream.
    Like Al said some (lots) of carbs work fine with out a nozzle.
    If the discharge hole is in a low pressure area fuel will come out of it.
    There are lots of Tilly carbs that don't have "nozzles"

  19. #19
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    Check that needle also on gas it has to be marked BGB if it is not it is alcohol BHA I think.

  20. #20
    Thanks everyone for the help, you're awesome. The kart will be running tonight, we'll see how it goes!

  21. #21
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    If the nozzle does not protrude into the WALBORO (BRIGGS) carburetor it is indicative of potential problems.

    The first problem is it is ILLEGAL. Find me a stock Walboro or Briggs carb that has a nozzle not protruding into the venturi. Furthermore, trimming it down COULD get you some performance change, but is illegal. Therefore, I assume there are builders who will try it.

    The second problem is it will not draw as much fuel which could be indicated by idling issues (as described by the poster). At least that is what I found when playing with ideas and testing the WALBORO carb. I didn't test KT100's or Tillotsons because I don't race those. I will assume that a KT idles (not that I have ever seen one idle as I have always at a bit higher RPM than the 206. I am NOT saying the engine will not perform, I am saying it will not idle as well. As Jimbo has told me a few times, we don't race at idle. However, idling issues was something the poster was having issues with and had to go to an extreme needle setting to make it idle.

    Not sure why all argumentative responses to my posts, but I am beginning to suspect maybe some other posters are feeling threatened when someone else has something to say or add because then they are not seen is the "expert" or "guru". Check your egos at the door because maybe, just maybe, you aren't the all knowing God's that your fame on 4-cycle has led you to believe that you have become.

  22. #22
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    I'm reminded of my ex-wife, I didn't always win arguments with her, but on occasion, when I was close, the next thing out of her mouth was "your so argumentative". "You think you know everything"! Thing is, even if I did get upset with her, I didn't start accusing her of all kinds of derogatory stuff.
    From the desk of Al Nunley 512-630-6215
    Comments compliments criticisms and questions always welcome.
    If the data does not support the theory, get a new theory. (Al Nunley)

  23. #23
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    Quote Originally Posted by alvin l nunley View Post
    I'm reminded of my ex-wife, I didn't always win arguments with her, but on occasion, when I was close, the next thing out of her mouth was "your so argumentative". "You think you know everything"! Thing is, even if I did get upset with her, I didn't start accusing her of all kinds of derogatory stuff.
    The key phrase is "my ex-wife". Perhaps if you listened to what she was saying and were able to reflect upon yourself and how others perceive you (which is different than who you may really be or how you perceive yourself) you might be calling her "my wife".

  24. #24

  25. #25
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    Quote Originally Posted by jjchat View Post
    The key phrase is "my ex-wife". Perhaps if you listened to what she was saying and were able to reflect upon yourself and how others perceive you (which is different than who you may really be or how you perceive yourself) you might be calling her "my wife".
    Yet you continue on!
    From the desk of Al Nunley 512-630-6215
    Comments compliments criticisms and questions always welcome.
    If the data does not support the theory, get a new theory. (Al Nunley)

  26. #26
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    Quote Originally Posted by alvin l nunley View Post
    Yet you continue on!
    Yes, if you insult me, even if it is a backhanded insinuation, I generally will retort. I'm not nice, remember....

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    Quote Originally Posted by jjchat View Post
    Yes, if you insult me, even if it is a backhanded insinuation, I generally will retort. I'm not nice, remember....
    And on and on and on...................
    From the desk of Al Nunley 512-630-6215
    Comments compliments criticisms and questions always welcome.
    If the data does not support the theory, get a new theory. (Al Nunley)

  28. #28
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    Quote Originally Posted by alvin l nunley View Post
    And on and on and on...................
    And on, and on, and on.....says the man with 7,319 posts.

  29. #29
    Many of us deal with this a lot in the N.W.

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