I remember my go kart when I was a kid it had the 5hp Tecumseh and a Comet Torq a verter on it, I took out the governor after my cousin showed me how and the carb had that high speed adjustment screw at the bottom of the bowl that was basically a needle screw that partially blocked the fuel flow thru the main jet.
I remember we took it out to a big drainage ditch shortly after we got it and were taking turns riding it when I noticed it just didn't have that "get up and go" that I felt on earlier rides, my cousin then pointed out the governor and told me about how to disable it or at least adjust it for more rpm so we did that, still a bit sluggish, but we rode it for about an hour or so, loaded it up in my dad's truck and brought it home.
I read the owner's manual to see if it had that troubleshooting section and sure enough, there was a symptom listed for being slow but it only talked about the throttle cable adjustment, but the manual for the engine showed the high speed screw... I tried it and noticed right aaway it was as fast as that first ride, then I screwed it in until it slowed down then retruned it back to it's quickest setting.
This thing would hit 45 in no time flat and beat everyone else's go karts except for another friend's racing kart with the KT100 engine in it... in which case it lost badly, but that's a totally different animal.
Once I got the carb tuned tho then basically set the governor so it wasn't closing the throttle at all I was out riding around and my mom took the car to where I said I would be to tell me to go home for dinner, I lead the way and she followed, then when we got home she asked if I knew how fast I was going and I replied "um... about 45 I guess" and she told me she was doing 60 behind me. I found that pretty easy to beleive since the cart had those 18" tall back tirres and that CVT also made it fly as well as having better acceleration than the other guys who just had the typical centrifugal clutches.
I kept that kart until I was about 18 years old but broke the rod after removing the governor completely and "borrowing" my dad's Honda Twinstar 185's carb.. it bolted right on and it was jetted just right, I remember the kart was quicker than it ever was going up the hill to get around the block, but when I was on the next street that was nice and flat I remember that thing must have been doing about 70 and BOOM!! then it slowly coasted down to a stop. I got off to try to re start it but when I pulled the rope I knew it was game over... it pulled real easy about half a turn then stopped dead. I pulled the torque converter cover off and turned the crank by hand and it was clear to me that something wasn't right so I pushed it home, took off the side case cover and sure enough, it snapped the rod right at the base, it was still bolted to the crank, but the beam snapped in half.
This of course was back in the mid 80's and with no internet I had to get another stock rod from a small engine shop. I remember asking the guy if they made a stronger rod for the engine and he simply told me there was no such thing. If I could have got a billet rod for that thing back then that engine would have been really awesome. I remember it also beat another friend's kart that was the same model but had the 8hp Tecumseh engine, his would take me off the line and accelerate better but it was no match for mine's top speed and he was always puzzled why he couldn't beat me with the stronger engine.