My daughter and I went to the track yesterday to get some seat time on our new karts.
Hers has a stock Honda GXH50 - on the stand it starts and seems to run fine. Once the rear tires touch the ground it dies. The idle rpm (on stand) was 1700. After many attempts and couldn’t get it to stay running I adjusted the idle 2300 (which the Honda manual said was normal - or + 200rpm) This didn’t help either. When the kart is sitting on the ground with tires touching its hard to pull the starter rope. So my best guess at this point is that the clutch is partially or fully engaged. as far as I know its the factory clutch.
Does it die on the stand if you use the brakes to hold the rear tires still? Definitely sounds like the clutch is failed. If a spring breaks, it engages too easily.
Are you confident the clutch was installed correctly? It is definitely not releasing from what it sounds like. Just open it up next and take a look. The problem will probably be pretty easy to spot once you do. In my case (different motor) when I had similar symptoms, the bits of clutch spring dumped out when I took the drum off, haha
I know my GHX50 was super cold blooded, it would not run unless it was fully up to temp. A trick I did especially on practice days was let him run a lap or 2 with the coke on 1/2 way to build heat then turn it off completely.
If the springs are fine, make sure that all of the spacers in this diagram are in the proper order. Its been awhile since we installed a new GX50 but I do recall having a similar issue for at least one customer kart and the problem was when running the retainer “nut” down, there was no play in the clutch. It was effectively a direct drive rather than a centrifugal clutch.
