Engine Trouble Starts for a few seconds then dies.

Discussion in '2-Stroke Engines' started by Louie, Aug 3, 2016.

  1. Louie

    Louie New Member

    Hi,
    My bike has been running well for 100 miles. Yesterday, it died just at the end of my 3 mile trip I make every day. 4 hours later, it was fine on the return trip. Today it died midway through the trip and wouldn't start for the return trip.
    When I drop the clutch, it turns over but dies out after a few seconds, and if I disengage the clutch it dies immediately. Im running 32:1 btw
    Here's what I've tried:
    I opened up the carb and cleaned it out (was clean anyways)
    Opened up the head and checked the rings. (they're fine)
    Tested the magneto (getting 370 ohm blue to ground)
    Didn't try leaning it out with the c-clip because I've been running it at the same position for a while, although the spark plug did seem a little wet. This could just be from all my failed attempts to start.
    I did notice that the exhaust pipe isn't completely flush against the exhaust manifold. Not sure if this could be the problem.

    What else could it be?

    EDIT: Just took off the exhaust cap and it had quite a bit of black oil in it. Not sure what that means.
     
    Last edited: Aug 3, 2016

  2. Frankfort MB's

    Frankfort MB's Well-Known Member

    That's probably your problem....
    Try and start the bike w/0 the cap on, probably clogged up the exhaust.

    Don't worry, there's nothing wrong with the oil in the exhaust all 2 strokes do it
     
  3. Louie

    Louie New Member

    Tried doing that, same problem.
     
  4. Frankfort MB's

    Frankfort MB's Well-Known Member

    Might also be a fuel lock on the gas tank, try to start bike W/O the gas cap on
     
  5. Louie

    Louie New Member

    I don't think it's that. When I took the carb off to clean it, fuel came gushing out of the fuel line because I forgot to close the pet cock. It's hard to tell if the problem is fuel or electrical because I get a little of both when I try to start it up.
     
  6. Louie

    Louie New Member

    Also, just tested the CDI resistance. Getting 7.4 kOhms from CDI black wire to spark plug cap. I believe that's about what it should be.
     
  7. Louie

    Louie New Member

    New NGK B6HS plug. No change
     
  8. crassius

    crassius Well-Known Member

    not turning petcock off when parked can fill motor with fuel - either keep it running until it clears out (may take a mile or so) or take out plug, unhook CDI and pedal motor till it all blows out

    indication that this has happened is oil in muffler & excessive smoke when it starts
     
  9. gary55

    gary55 Active Member

    Sounds like it should be running fine. Don't hate me for mentioning these two things cause I know it sounds dumb, but is the nut on the choke lever tight? Sometimes they get loose and vibrate the choke closed when riding. How about the connector at the plug end of the wire. Sometimes they will break but still work intermittently. The only reason I bring these up is cause it sounds like everything is good.
     
  10. Louie

    Louie New Member

    Tried taking out plug and unhooking CDI and pedaling around for about 5 minutes. Nothing. Also I tested the plug and did get a spark. Not sure how bright it should look but i did see one.

    My choke is fine, and I'm not sure how to check whether the plug connector is good.

    I did notice that riding around with the plug removed actually sounded like the engine running, so maybe I'm confusing that sound for getting a spark when I try to start it. What could cause a weak spark?
     
  11. gary55

    gary55 Active Member

    Man this is a tough one. In these situations it seems that you have done all the things I would have done. The spark is weak on the stock cdi's, but if you are seeing spark at the plug I think we can eliminate electrical. So now were at fuel, air, and compression. New bike so the filter is not clogged. We got air. Even if the head was warped I think it would start and run just poorly. So were stuck at fuel or air fuel mixture. My next move would be to check the needle to make sure I put the pac man clip back in properly holding the needle down in the barrel. Hit the tickler on the carb a few times watching for fuel movement in the line, and try to start it. If none of this worked I would take a look at the crank seals behind the small crank gear and magnet on the other side to see if they are popped out. Usually if there is a leak here there are some signs of fuel in the covers. It's stumping me so it must really be driving you nuts.
     
  12. crassius

    crassius Well-Known Member

    you're in a bad place for a new rider - I have a compression gauge and a CDI tester that can tell me a lot about a dead motor when it comes in for repair - sometimes when everything looks right, I know to just keep pedaling and it will eventually start

    you might want to try loosening the muffler 1/8inch or so so you will certainly hear a pop if it tries to start, then put several drops of fuel in spark plug hole and new plug and see if it pops
     
  13. gary55

    gary55 Active Member

    I just learned two new trouble shooting methods. Thanks crassius sometimes the things that are right in front of my face are the hardest to see.
     
  14. Louie

    Louie New Member

    UPDATE:
    Was going to call it quits for the day. All I did was put the muffler cap back on and then hit the tickler a bunch until fuel was dripping out of the idle screw. I had already done that before and checked for movement and it was fine. This time, I took it out and managed to get it to cough to life. I rode around the block, about a half mile. Ride was a little rough but fine. Got it back in the driveway and was letting it idle while I looked for a screwdriver to adjust idle speed (seemed to lose a lot of revs whenever I disengaged the clutch). It died while it was idling. When I went back out to get it started again, I had the same issue as before, going for a second then dying.
     
  15. Frankfort MB's

    Frankfort MB's Well-Known Member

    Your having fuel issues.... Somewhere From the tank to the cylinder your having a problem
    (I know right? So specific.... Gotta love these things;))
     
  16. Louie

    Louie New Member

    I figured as much haha. I guess I'll have to look at the carb again. keep the suggestions coming!
     
  17. Frankfort MB's

    Frankfort MB's Well-Known Member

    Check your spark plugs color.... Sometimes fuel mixture will cause problems
     
  18. Louie

    Louie New Member

    Spark plug is a nice tan.
    Just took the bike out again without changing anything. Ran well for about five minutes, then cut out, then started up again when I tried. Already a lot of oil in the exhaust. Is there anything that could be causing a rich condition? I have the clip set the one from the top, so I don't think moving it to the top notch will do much.
     
  19. Frankfort MB's

    Frankfort MB's Well-Known Member

    You might be running lean. That could cause the engine to stop.... I'd get another opinion on it
     
  20. jaguar

    jaguar Well-Known Member

    going bad when hot is either head gasket leak or stator coil.
    plane your head truly flat using sandpaper on glass and make your own head gasket out of hi temp gasket material. throw that junk aluminum one away!
    stator coil output can go bad when hot if the screw head to stator frame connection isn't clean metal to metal.
    also stator winding can be broken but touching enough to conduct while cold but not when hot.
     
Loading...