CNS Carb Problem?

Hello again! I recently got my CNS carb and it is pretty cool. I have a few questions or trouble shooting inquires. For some reason, when riding with the fuel petcock switched to on, the motor looses its acceleration (and slows down) once I hit 30 MPH. The funny thing is, though, if it turn the petcock off, the motor will continue to accelerate to 37 MPH and although it wont go faster, the RPM wont slow down. What is wrong?

Rich probably look at the plug for blackness.

If it is dark then lean it out

The tab the is above the spark is dark, but the sparker is a light brown. I don't think this is right because it works fine if the petcock is turned to off. As soon as it is on, the carb has a problem delivering gas at the same time as retrieving more.

So does anyone have any ideas?

Tuning carburetors requires study and dedication to the craft.

I could be the float level or fuel surge or a big main jet or the wrong needle.

Read a manual, this is a good one

http://www.thisoldtractor.com/gtbend...rto_manual.pdf

Yes, run it with the petcock off.

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If it ain't broke, and you mess with it long enough, it will be.

If it runs good with it in the "off" position, read the plug after you ride it around for an hour or so.

Remember- never remove a hot spark plug! Use Never sieze if you have it when you re-install it. If you don't have some, use some graphite on the threads, a pencil will work in a pinch.

__________________
If it ain't broke, and you mess with it long enough, it will be.