I just brought a new carb for my ATV and now when i start it it is revin really high and it's in neutral can anyone help thanks a lot?

I'm no expert, but I can think of several potential causes for that:

- Is the throttle cable fitted / adjusted properly after the carb change (ie. releasing the throttle grip completely to idle, does let the throttle lever of the carb fully return to idle)?

- The carb should have an idle adjustment screw. Try loosening it for a lower idle revs.

- Is the choke working properly? Is it possible that it's engaged when it shouldn't be?

- Is the carb identical (as type) with the old one (ie. is it the proper type for the given vehicle)? Are there any special/different jets in it?

- If all else is negative, it's possibly something about the way the carb is fitted: are the intake / outlet fitted airtight, using the proper gaskets? Especially the carb - cylinder head manifold? If spraying water around the gaskets causes changes in the revving, it's not airtight.

If none of this helps, the problem is way beyond DIY level - get a proper mechanic to look at it...