Sputters but no start.

Discussion in '2-Stroke Engines' started by Jixz, Jun 13, 2008.

  1. Jixz

    Jixz Member

    I have a kings 80 cc motor and the rest of the kit is Boy go fast.. I cant seem to get this thing up and running. Im getting a spark from the spark plug, ive used two different carbs. ( both getting fuel ok ), and ive tried the carb lever at almost every position. The best i can get it to do is sputter a bit .. but never any more than two consecutive cycles. I have no clue what could be wrong.. i dont even have the kill switch in.

  2. dancycle

    dancycle Guest

    same prob

    I've been having the same problem. It started when I made a bad mix of gas using gas that had been sitting around a while. Slowly the engine weakened, but now that I have put in fresh gas, cleaned out the carb, checked for a spark, etc., the motor just won't run. I get hiccups of the engine firing every few seconds, but I cannot get it to get up and running no matter how much I mess with the engine. I have pedaled the bike for a mile with this intermittent firing but it just doesn't start running on its own. Any help or suggestions would be greatly appreciated.
  3. Marktur

    Marktur Member

    OK, silly things first...do you have good connections between motor and CDI?
    Get rid of the kill switch.
    Make sure the fuel petcock is on (pointing in the same direction as the fuel line.
    Press the button on the carb to let the fuel in.
    Pull the choke all the way up.
    Do not give it gas while the choke is on.
    Once it fires up, pull in the clutch and stop moving....close the choke all the way...let the motor warm up before you start revving it up.
    Take the idle screw, turn it all the way in (just until it stops - NOT TIGHT) then back it out 4 full turns. Out further slows down the idle, in speeds it up.

    I know you checked the spark, and have fresh gas...that just leaves compression - which I'm assuming is there, and air/fuel mix. I don't know how the air is in Oregon, but maybe some of the guys from out West can tell you where the e-clip on the carb needle should go.

    ****, look at me - computer guy trying to help someone get a motor running! Who'd thunk that would ever happen??? :)

    Good luck, and keep up posted...what I listed are what I think "basic" things for troubleshooting.
  4. Check the adjustment on your clutch to make sure the engine is engaging. Sometimes it might seem like it is, but it is just slipping and catching every few revolutions, not enough to draw air and gas in the carby...
  5. jared3377

    jared3377 Member

    Haha! Hey, we all have multiple talents, don't we...? :smile:
  6. If you have A good strong spark ,Plug is good .Gas/ oil mixture Fresh and correct.
    Good compression and nothing blocking both air and exhaust then motor should run.How's the plug look after you try starting it.?


  7. Jixz

    Jixz Member

    ok, spark plug is good, ive changed out the gas with a new tank of 16:1 ratio, the carby seems to have gas in its bowl, chains tight (not too tight), kill switch isn't even there, clutch seems to be ok ( tell me how to check for sure ).

    The only thing i can possibly see wrong with anything here is the fact that its a different CDI, Exhaust, and Carb.. Tell me if that matters?
  8. Marktur

    Marktur Member

    Too much oil maybe? I'm running like 35:1 synthetic. Maybe add a bit more gas to the mix and see how it goes if all else fails? I think you should break in at 20:1, right? This is about my limit of usable knowledge, the rest if just guessing! :)
  9. Marktur

    Marktur Member

    If you can hold in the clutch, pedal and coast, you're good with the clutch. It should turn over the motor when the clutch is released. If it slips while released and doesn't always turn over the motor, then maybe the clutch is not tight enough. Mine just works, right out of the box...it chirps while I'm riding, but I don't think it's slipping.
  10. What do u meen diff CDI, Exhaust and Carb?
  11. Jixz

    Jixz Member

    i mean those are boy go fast, while the physical motor is kings motor bikes brand
  12. Jixz

    Jixz Member

    err, im beging to loose hope here. Is there a chance that the CDI is operates on a deferent voltage so its not getting the spark it needs to start the combustion?
  13. Marktur

    Marktur Member

    REPLACE THE PARTS IN QUESTION: $25 to not lose hope...same for the carby....and if no change, then you know they're fine...sell them on eBay and get most of your money back...or keep them for spares.

    A motor needs 3 ingredients to run:
    1. Fuel
    2. Air
    3. Spark

    The fuel and air are Carb adjustments...the spark is CDI.
    If you can verify the spark, well, I'd replace the carb.
    I'd also use new fuel at a 30:1 ratio...I've mentioned this before, I think you're pushing too much oil through at 15:1...

    If you pull off the fuel line from the carb, and open the petcock, does fuel run out? If not, your filter/screen is clogged and it's starving for fuel.

    If you pull off the air filter, do you see any debris clogging up the air passage? If not, then your carb should be fine.

    Where is your idle adjustment screw? Should start at 4 turns out (full 360 turns)

    Where is the e-clip on your needle? Make sure it's on the second one from the end. This is the stock setup.

    Finally - have you verified a spark? Replace the plug with the other one that came with the motor...if you don't have one, pickup the NGK one (search NGK spark plug for the one you need, I can't remember).

    OK, if everything seems good above, let's look at how you're going about starting the bike...

    Firstly, when you pull in the clutch, does it roll smoothly? There should be no resistance. If there is, that's what's not letting it idle.

    Secondly, when you try to start it, are you fiddling around with the choke? I start mine choke all the way up, once it starts, I immediately pull the clutch in so it will idle - giving it NO THROTTLE, because that kills it right away, then I reach down and close the choke 100%. THEN, and only then, can I give it throttle and hear the motor run up.

    After that I do not use the choke any more, for subsequent starts once it's been run, all day long.

    Now, I'm in FL at sea level, and I don't know what the differences are in your area, but I think all these things listed about should apply. Don't give up at this point, because once you do get it running, you'll be the "guru"! :)

    Good luck...and when you get frustrated, just walk away from it for a bit.
  14. Madwack

    Madwack Member

    these guys are so right about removing that kill switch as i stated in another message ..i road my bike up and down the alley fer 2 days...most i got was a sputter...actually i got it going once...then i stopped...ouhps...wouldnt start again..anyhow long story short..i checked everything just like you.....old fella down the lane said ..check yer wiring..so i went back and undid that killswitch....left the other wires intact...Vrrrrrooooom :cool:

    gonna take a wild guess here..but the spring in that kill switch is sucky ....must been bouncing and killing the engine :(

    hope that helps

  15. Jixz

    Jixz Member

    hehe, i love the old guy down the street. hes helped me so many times.