Engine starts, then poops out on me

Discussion in '2-Stroke Engines' started by (Ian), May 13, 2010.

  1. (Ian)

    (Ian) Member

    When I run it downhill it's great and I can tell it's accelerating, but when at the bottom hill it sputters out and stops. On even ground/uphill throttle revs the motor but doesn't make me accelerate, and sputters out like before. First bike. Using upgraded air filter. Tried using the standard air filter but this made it worse.

  2. 210061741

    210061741 Guest

    What dose the spark plug look like.
    Wet, Dry, Color,

    What do you have the plug gap set to?

    Sounds to me like it's possible you have a bad coil.
    With a week coil the OHM's will read correct on a meter but during runing the coil is shorting out.

    I have had this problem in he past and found the tiny ground lead coming from the coil to the metal plates had a small crack in it and was shorting out.

    Pull the plug and put in a new one with a very small gap.
    Like .015 which is smaller than you want it to be.

    If it runs better...not perfect but better that would be my first guess.

    Tell me about the sparkplug and we may have more clues.
  3. motorpsycho

    motorpsycho Active Member

    of corse it will run good going down hill. you have all the momentum "pushing" the motor to accelerate (the wheel starts to push the chain around the engine sprocket, rather than the engine pulling the chain around the wheel sprocket).
    it sounds to me like a fuel problem....either a plugged up screen in the tank, a kink in the fuel line, or a misadjusted float. sounds like the carb is running out of gas.
    no acceleration (forward movement of you and the bike) on flat ground when you give it throttle, could just be that the clutch is out of adjustment.
    if the engine revs (like you say it does) and you do not move...the clutch is slipping. that's the only possible answer for that scenario... unless you are trying to ride it with the clutch disengaged. (clutch handle squeezed in)
    Last edited: May 13, 2010
  4. 210061741

    210061741 Guest

    I have seen alot of slipping clutches.

    And the fule thing is possible but i would expect it would pull for a breif moment until the carb bowl ran dry of gas.

    Either way a quick look at the Sparkplug will tell alot.
  5. Al.Fisherman

    Al.Fisherman Active Member

    I'd start with fuel/clutch as Motorphycso described. Heck I myself sputter going up hill. That's why I ride one of these....
  6. (Ian)

    (Ian) Member

    Thanks for your replies. It could be the clutch slipping... Not the fuel line, there's plenty of fuel in the carb bowl. How do I fix it?
  7. (Ian)

    (Ian) Member

    What do you mean by clutch slipping, actually? My clutch feels pretty tight. With it stopped and disengaged, I can barely push it...barely. I am able to and it makes the engine puff. Kind of not mechanically experienced.
  8. (Ian)

    (Ian) Member

    As for the spark plug it's the default one that came with my Grubee engine.
  9. (Ian)

    (Ian) Member

    I figured I'd just keep riding and see if it'd kick in. No luck. Actually, when I do down the same hill it turned over for the first time, it doesn't accelerate anymore.
  10. 210061741

    210061741 Guest

    Its the coil.
    Or it's wired wrong.
    Check it with a voltmeter.
    Should have between 325 and 350 ohms resistance between the black wire= ground and blue wire = Hot off the coil.

    Other than that id be looking at the kill switch.

    And i mean if you try to start the motor. Then take out the spark plug.
    Is it wet ???
  11. (Ian)

    (Ian) Member

    210061741, I took your advice and checked the spark plug. I don't know how to use a voltmeter, but the plug was wet. On a whim I replaced the plug, to see if that would help. Great success! My friend who installed the plug had removed the top contactor bit, said it wouldn't fit and should be fine without it. But then I replaced the spark plug wire with an upgraded one anyway. It must not have been making contact. However, I've since discovered some new problems:

    1)Leaky fuel valve. Flooded my carb when it wasn't even turned on! I've yet to find a perfect spot to put it in so I'm just disconnecting it each time. I bought an upgraded one that feels much better but I can't get it to fit on with the beefy upper frame. :-(

    2) Engine is missing strokes. It seems to work better when I'm not giving it as much throttle, but it still is. This results in a pretty shaky ride. At first it took off nice and soooo smooth, then I guess it must have loosened up.
  12. 210061741

    210061741 Guest

    Glad to hear you got your spark problem straitened out.

    Now your not missing strokes your 4 stroking.

    That's what happens when the engine gets too much fuel.

    You said the carb was leaking so i would get that under control first.

    You may need to take the bowl off the carb and bend the little brass arms down just a hair more.

    That makes the float close the needle valve sooner.

    Then the carb shouldn't leak if the float is right.

    After you haqve that under control if it is still 4 stroking you will need to unscrew the top of the carb.

    Take the slide out and compress the spring and get the needle out.

    Move the clip up 1 notch at a time till it runs right.

    Also check the nut that keeps the choke attached to the carb.

    If it's loose the chocke will close from vibrations and thn i will 4 stroke.

    Good luch
  13. (Ian)

    (Ian) Member

    Thanks again. Unfortunately I got on my back just an hour later and had the same problems I originally did. :-(
  14. 210061741

    210061741 Guest

    Well it sounds to me like the plug is fouling out.

    I bet if you take a razor Blade and scrape the electrodes a little and set a smaller than normal gap it will start up.

    And if it dose it's that pesky ground wire coming off the side of the coil through the bakelite and soldered to the steel plate.

    Get it running with the magneto cover off.
    Look at the coil and see if it is arching out somewhere.

    Other posibility is your carb is filling the engine with gas when it leaks.

    Causing it to flood out right away.
  15. (Ian)

    (Ian) Member

    It wasn't flooding this time. I took the carb apart and shook the fuel out after it was flooded, and it hasn't happened since. I think it was flooding because the engine wasn't really burning it. It made noise, but the muffler wasn't getting too hot and there was no smoke.
  16. 210061741

    210061741 Guest

    It wasn't runnin thats 4 sure.

    You will see some smoke.

    I'd be pretty positive you willfind that the coil is bad.

    Not the cdi but the coil.

    The cdi is the black box the coil is under the little rectangular cover on the engine.

    Try this.

    Take the spark plug out.
    Use a new spark plug like a NGK B6HS.

    Put the Spark Plug in the wire.
    Place the threaded end on bare metal of the engine.
    Walk the bike forward real fast and see if you get a good blue spark.

    If it's more of an orange color or no spark at all it's a bad coil.

    I have 3 or 4 bad coils from new engines. It's common
  17. Hajuu

    Hajuu Member

    Sounds to me kinda like an air leak. Air leaks either on intake, exhaust, or on the head will cause immense loss of power, but usually only under high load.

    Or the clutch maybe, but if its going full speed downhill and accellerating to full revs, then it seems unlikely itd be the clutch or the electrics.
  18. will_start

    will_start Member

    Can you stop and rev the engine ?
    thats my test if my bike is working.

    My electrical plug test is crude but works.
    Drink six beers, take the plug out, and hold it in your hand.
    move the bike around, with clutch out, and feel the spark.
    Feel the motor and how it sounds raw.
    If my bikes not working, this gets me in touch with the motor.

    Simple, No Pain, No Spark, just like an Ex Wife.

    This should work even with highly compressed motors
    as you've taken the tension out by removing the plug.
    Smell the fuel and get a bit more high.

    The beer helps stop the pain of the electrics.

    Try it some time if you have the balls.
    Last edited: May 15, 2010

    SSGSPOD New Member

    Spark not constant.....check rotor.

    It may not be applicable to your case, but you should check it out.

    My brand new engine had definite spark issues....no constant timed spark.
    Pulled cover off, found deformed lock washer in the bottom, rotor was loose.
    upon inspection, found the crankshaft key on the back of the rotor, rotor was freewheeling on the shaft, chewing up the lockwasher & nut, and stripping the threads on the crankshaft.

    Rotor was hit and missing spark depending on how fast it was slipping on the shaft.

    Motor must have been assembled on a Monday morning......

  20. 210061741

    210061741 Guest

    I have seen several Grubee engines with no key or a key thats too small in the magnet.

    It's a spark issue for sure.

    Trust me i have fought it mayn times.