Engine Trouble Engine cutting out when clutch is engaged

Discussion in '2-Stroke Engines' started by ilovenxtage, Apr 14, 2013.

  1. ilovenxtage

    ilovenxtage New Member

    My Chinese 66cc engine is cutting out and bogging when my clutch is engaged, but it runs fine when I disengage the clutch and coast. Everything is stock. The chain does produce a lot of friction because the stock chain tensioner doesn't mount perfectly to my Diamondback hybrid frame, and the chain kind of bounces when the clutch is engaged. I wasn't having this problem before, it suddenly started happening.

  2. Rusty Biker

    Rusty Biker New Member

    I'm a newbee here but is it something as obvious as the idler setting?
  3. BAZZA614

    BAZZA614 Member

    i would get a link or 2 taken out of the chain. i had the same problem with my chain. also like the guy said above me i think its the idle screw
  4. Rusty Biker

    Rusty Biker New Member

    That's something I learnt recently, that as the engine breaks in the idler needs to be adjusted because the engine changes and becomes more powerful.
  5. jaguar

    jaguar Well-Known Member

    An engine under load needs a richer fuel/air mixture than the same engine with no load (clutching it). So yours obviously is too lean. Since it is sudden onset it is most likely caused by an air leak. That usually happens between the engine and the carb. But it can also happen at the crank seals. Lucky for you they can be replaced without taking apart the engine. Most unlikely but still possible scenario is that some trash is partially blocking fuel flow in the jet. Take the jet off and look thru it to see if the hole is still round. Stick the wire from a bread tie into it and maybe also spray carb cleaner into it. Let me know the outcome.
    oh also it may be head gasket leak because that would ruin compression which would show up mostly under a engine load situation.
  6. ilovenxtage

    ilovenxtage New Member

    I'll check for air leaks, and I'll check the fuel jet. I doubt it's the head gasket because I have LOTS of compression. It's also four stroking a lot. Isn't that caused by it running too rich, or am I wrong? I'm still new to two strokes.
  7. ilovenxtage

    ilovenxtage New Member

    OK, I checked the fuel jet and it was clean, and there seem to be no air leaks anywhere. I did notice the spark plug connector was barely attached to the cable. I pressed the cable on further and temporarily secured it with electrical tape (I'm going to get a better CDI and coil) and there was no cutting out. Maybe the increased vibration when the engine is running under load was jiggling that loose connection. It is still four stroking almost constantly, and the plug was wet with fuel when I removed it so it must be running rich. There are no obstructions in the air filter and it is clean.
  8. KCvale

    KCvale Motorized Bicycle Vendor

    What Chinese 2-stroke do you have, and what kind of carb?
  9. ilovenxtage

    ilovenxtage New Member

    I don't remember the brand because I first bought the engine five years ago and never got around to doing the build till now. I got it from Kings Motor Bikes. It has the stock carb with the black circular air cleaner cover. (Sorry that's not much help)