i have the same motor on my gokart, a tecumse 5HP, i wasnt impressed when i bought it brand new and put it on the kart,it would only go 15mph, but i altered the governor springs on the throttle and now it goes 30mph with no problem....my friend has a kart with an identical motor but different gear ratios so he can hit almost 40 on his, but i smoke him off the line and can get through tougher situations than he can cause mine has torque like crazy......only thing is i lost the end of my left pointer finger in the clutch and chain at top speed, all i can say about that is OUCH!!!! but man they are fun, im 28 and STILL love riding them whenever i can........