I installed an NR racing stage II kit in my Honda GX 270 . It included a cam /springs 4 degree key, intake manifold, air filter, a bored 390 Gx carb plus Robertson H loop exhaust system. The carb is 23.5 mm bore a .037 main and a .025 pilot with a stock E tube . The kit installed easily and the motor fired right up and idled smoothly . The problem is when the throttle is opened the engine starts stumbling and will not rev at all . I am hoping someone out there may have experience with this issue and point me in the right direction.
https://www.youtube.com/watch?v=9nNXWVA0Cuk&feature=youtu.be
https://www.youtube.com/watch?v=9nNXWVA0Cuk&feature=youtu.be