REVVing issue

Discussion in '2-Stroke Engines' started by jmr3394, May 9, 2010.

  1. jmr3394

    jmr3394 Member

    Every time the rpms reach a certain number or i go 20 mph the rpms drop very low and slowly climb back up. I just added a new air filter could this be the problem? Need help please. Any suggestions or comments?

  2. Flapdoodle

    Flapdoodle Member

    Sounds to me like it may be starving for fuel, such as an obstruction in the line somewhere. With a better air filter it may be using a little more fuel.

    The plug color may give you a clue.
  3. motorpsycho

    motorpsycho Active Member

    starving for fuel (float level) or it's running too lean (air/fuel mixture).
  4. Al.Fisherman

    Al.Fisherman Active Member

    What a question, don't know how anyone can answer this one. One of the MOST important things when asking questions is to tell us what you are working on. There are many types of engines and many types of carburators...if we are working on a gravity fed system (which I'm guessing we are)....Check in tank screen, in line filter if you have one..if not install one, and float level. After that on to the needle and seat. Some engines have a fuel pump. Some have no float.
    You just changed air filter...go back with origional filter and check again. Different filters different air flow different air/fuel mixture.
    Last edited: May 10, 2010
  5. jmr3394

    jmr3394 Member

    Im working on a Grubee Skyhawk 2 stroke 48cc. I just added the high flow air filter from SBP and today I was tinkering around I took off the CDI cord and the gold metal thing inside fell out. I replaced it and started it up and it seems like its running alright now but it was only idling so im not sure yet. Could this have been the problem? Also i don't know how to check the float levels or leaness of the gas and stuff. Comments please :)
  6. jmr3394

    jmr3394 Member

    FIXED!!!!!!!!! Ok all along i thought it was an electrical issue BUT today i decided to just run through and make sure everything was tight on the engine (bolts, screws, etc....) Turns out the bolts that attached the intake manifold to the cylinder were quite loose. I started her up and she runs like a pro now.
  7. MikeJ

    MikeJ Member

    Good for you! Thanks for the helpful feedback. My engine has similar symptoms; maybe the same problem.
  8. Al.Fisherman

    Al.Fisherman Active Member

    Upgrade the hardware if you haven't done so already. Use either use double nuts to lock, or self locking nylon nuts.