New here.

I bought my 8 year old a Viper 90R that wasn’t running. I took the carb apart and cleaned it out and replaced all of the fuel lines and petcock. The quad ran ok after that, although it would sputter at higher speeds. Fast forward a few months and now it starts without using the choke and revs ridiculously high until I shut it off (bogs when i rev it, recovers when I let the throttle go), then it starts at normal RPMs. The throttle surges occasionally while he’s driving it and sometimes he can’t stop the quad until the revs drop because it overpowers the brakes. I’m thinking about taking the carb apart and cleaning it again or just replacing it, but wanted to know if anyone had any other ideas as to what it could be.

Thanks

 

Check the throttle cable for sticking and replace if faulty. Otherwise it is a matter of cleaning the carb out again. Make sure there are no air leaks in the inlet manifold, though not needing choke would indicate this isn't your problem.