What I am currently up against...

1. The engine will start and run fine under no load.

2. While running under no load, it idles high. Adjusting the Idle set screw and the high speed idle screw have ZERO effect on the idle...I can actually remove both and the Kart runs and idles high

3. Choke will slow the idle speed.

4. Putting the Kart in gear and driving slows the engine speed, engine has no power under load with the Kart moving at the speed of a fast walk and stopping under any kind of load. Lifting the foot of the gas pedal while in gear will stall the engine.

5. I replaced the carb with a unit off of a CT70 (Keihin 19mm) that runs great on the bike...putting it on the Kart resulted in the same behavior as above.

6. So here I am, a Kart that will start, idle high, has no performance under load. Kart has new Stator, and CDI...

7. I am thinking I may have an air leak somewhere cuasing the kart to run lean, maybe bad head gasket or a clogged exhaust / exhaust port, bad exhaust valve...Kart has maybe 2 hours on it...has been nothing but a headache...

8. Welcome your thoughts / suggestions...On a related note, can anyone recommend a reliable Kart for a 9 year old...any non-Chinese Karts out there

Thanks

sounds to me you know what you are doing .Spray carb cleaner around the intake manifold see if it changes idle speed.If it does you have a leak. I would do is run a comp test valves may need adjustment.The chinese buggys are known for this.
hope this helps.

like funnyman said possible vacumn leak. check the gaskets between the carb and intake and head and intake, also check the muffler for baffles that have came loose. take it off and shake it good.

adjusting the valves helps alot on those little motors. the valve clearance is 0.002, ( 2 thousands ).

Thanks for the responses...Any tricks to adjusting the valves...On the CT70 there are marks for valve adjustment on the fly wheel, any such luck on this engine, or is it TDC on the compression stroke...

If the exhaust baffles are loose in the muffler, what is the fix...

Thanks

Just throwing this out there,
check your intake manifold. We have had a couple that were a quarter size on one end and a dime size on the other end.
Also, the clip on the carb needle might need to be raised or lowered according to your altitude.

the muffler fix is to cut it open and remove any loose parts or replace it. we just do tdc on compression stroke for the valves. Like Tom said there have been some with tiny intakes on them. also move the ground wire from the electrical box and lengthen it and put it on one of the starter mounting bolts, those things have always had ecletrical issues and that was the fix we found