carb problem

Discussion in '2-Stroke Engines' started by nick8686, Jan 3, 2008.

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  1. nick8686

    nick8686 Guest

    hi my name is nick the problem is when i hit the gas it just dives in rpms, no power and struggles its way back up; no tourqe at all some time it almost stalls I've moved the needles up and down and it has good spark, is it the float? or something in the venturi? or jet ? help please im stuck on it any ideas would be appreciated .ps did i get the right form? dont mean to over post
    Last edited by a moderator: Apr 13, 2008

  2. mickey

    mickey Guest

    I see from your intro that you have a spookytooth so you have the HappyTime 2 stroke engine. How old is the motor? What oil/gas mix are you running? Does the problem occur at any speed? If your going 20mph and open the throttle all the way, does it stumble then, or just at slow speeds? Has it had this problem since it was new, or has it just started?
  3. nick8686

    nick8686 Guest

    thank you

    the engin is one year old i use a 2 stroke gas mix thing it had gr8 power all through the throtel up till just a few weeks ago probobly like 700mi on it just lost power a week a go ,it sits for weeks at a time .when going 20 it will run ok and gain in rpms and speed but feels like it has no tourq .From 5mph to 15mph it dives on rpms and sputers almost stalling for like 100 feet or so and then picks up im stump and i know im no guenuus at carbs so thank you for any help
  4. mickey

    mickey Guest

    You say that you have good fire on the plug. How do you know that? How old is the spark plug? Have you tried replacing it? Is the plug wet? sooted up? Black? White?

    Not to belabor the obvious, but fire needs three things, fuel, oxygen and ignition, all in the right mixture, whether its a fireplace or an engine. Work the diagnosis from that perspective.
  5. nick8686

    nick8686 Guest


    i uesd a oseloscope at work to check the kvs dwell and all that junk looked good new plug 2 weeks old and a bit brown i know electronick just not carbs
  6. mickey

    mickey Guest

    So you have fire, good. I'm trying to decide if you're getting too much fuel or too little. Are you drowning or starving :grin: If you slowly accelerate to wide open throttle, does it stumble then or will it go fine for some seconds and then start to stumble? In other words, is the fact that you're at WOT (wide open throttle/full throttle) the problem or when you snap it to WOT? Is stumbling the right way to describe your problem?
    Last edited by a moderator: Apr 13, 2008
  7. Poor performance/carb issues

    Hi Nick, too bad I did not know this a couple days ago as I leave here at 1:30pm.

    I rarely answer these type of posts, as it's been covered here many times.

    First, how old is your fuel, and what is your mixture ratio?

    Second, have you put an O-Ring INSIDE the carb to seal the potental air leak at the manifold/carb connection?

    Third, there is an odd tendancy of some of these engines blowing intake manifold gaskets, a VERY easy repair!

    Fourth, this happens too often to suit me, and that is the crankshaft seals sometimes go bad, and leak fuel mixture into the side covers, and sucking in air, causing a case-type vacuum leak.

    Check these things, and you should find something.

  8. nick8686

    nick8686 Guest


    well lots of stuf to look at and try new angals are a good thing will start as soon as me and the wife get home from erans thanks evory one ill be back
  9. fetor56

    fetor56 Guest

    I know this sounds obvious nick but have u checked to make sure the choke is not engaging as your riding....plenty of people have been caught like this.
  10. mnbiker

    mnbiker Guest

    Have you cleaned the carb? Have you messed with the adjustments?
  11. Papasaun

    Papasaun Guest

    Bump topic.

    Good basic diagnostic stuff for poorly running engines
  12. Papasaun

    Papasaun Guest

    Remove the float bowl from the carb. leave the carb installed on the engine. Put something under the carb to catch fuel and, then open the fuel shut off valve. Let about 2 or 3 tablespoons full of fuel drain. Did it quit flowing? remove the gas cap and see if the flow starts back up or increases. You might have a cap that is not venting! CLEAN is the most important word here. Clean tank, clean intake screen on the shut off valve and clean float bowl. It will not take much of anything to stop the flow of fuel.

    If you go to the trouble to clean all of the above, why not put an inline filter on now. This will insure that nothing gets back into the float bowl of the carb. If you wait untill later, you might still get gunk in there and have to remove the float bowl again.

    Last edited by a moderator: Feb 9, 2008
  13. fastboy9

    fastboy9 Member

    I had this problem of the tank causing a vacuum, simple way to solve is just to drill a very small hole in the top of the fuel cap.
  14. stealthc9

    stealthc9 Member

    sounds more like clutch issue to me
  15. Junster

    Junster Member

    Nick check the head for oil around the gasket. Re-torque the headbolts if there is any. My bike did exactly the same thing. Got less and less torque, my head was leaking losing compression. I hope that's what it is cause that's a easy fix. GL