Love You Long Time, but not happy time...

[woodyvt]

What is your elevation? It sounds to me like it's running lean and you may want to adjust your fuel jet size. I was just reading some threads on that and I believe that is my problem... mine is running too rich.

Just a thought...

 

[Junster]

Just a thought, Is the slotted plate that goes between the needle assembly and the slide return spring in there? It keeps the needle from sliding up when the carb slide drops. Seems like even a bad air leak couldn't do that much rpm without alot of gas to go with it. I know with my motor I had to use a wide flat file to true both ends of the intake tube (carb end too) and the cylinder intake port gasket surface to get a good seal. They were anything but flat.

 

[BoltsMissing]

my dollars worth;
After all the probing, if you have a stock carby, try that and see if it revs, just incase it ain't carby/manifold related air leak.

If it runs normal with a stock carby, then at least you know it's somewhere around the current carby, sort of a elimination process.

 

[Gungatim]

I will echo what Junster said--had the exact same thing happen with a carb on a Chinese ATV. the slide may be down, but the needle may be sticking. I modified a small washer to go over the needle, it is held down by the spring to ensure the needle doesn't stick. This cured my problem 100%, and it sounds like you may be experiencing the same situation. Give it a try and let us know...

 

[Skyliner70cc]

Just get a new carb and see if that helps.

 

[V 35]

I'd swap carbs

I believe a part that works, is better than a brand new, in the box, one.

Since the Carb is a low priced item, buy another one, just to see if it
solves the problem, if not, add some fuel stabilizer, ride to load carb with stabilized fuel, remove, drain, and wrap it up as a working spare.

Since there is no mechanical governor, and the intake is sealing OK
there must be an issue with carb. or throttle control.

Just for kicks, dangle the carb slide on end of cable, and gently work throttle while watching action.