Hey guys, I have a predator 2l2cc on my son racing kart. Engine mods are 22lb springs, govenor removed, higher compression head that's been ported a lil bit, jetted carb, and advanced timing key. Ran great all last year, now when I pull it to start the whole kart comes up off the ground lol. But if I pull it slow n catch it just right, it spins over easy and starts right up. Please tell me what it could possibly be anybody. Thanks