Hey, i have this 3 wheeler that had been sitting for a long time. one day i decided to pull it out and start working on it. i can get it to start if i hold the throttle down. but if i dont hold it down it wont start up. it doesnt idle. it just revs up. my muffler makes a loud poping nosie and gas is leaking out of the carb. through the two tubes.

Any help?

 

remove and clean the carburetor, stripping it right down and making sure that you use a fine wire to clean all the passages\ports. Or get a rebuild kit for it. Here is a link for the service manual that you can download and print.

http://www.oscarmayer.net/atc/manual...ice_Manual.pdf

Sounds like your float is stuck, and you are getting gas feeding into the carb by gravity with nothing to stop it. Excess flows out the overflow tubes, and if the throttle is wide open there is enough air getting in to combust the fuel, at idle there is not enough air for the amount of fuel.