If it didn't have the governor spring, the flyweights would hold the throttle in the idle position. UNLESS..... the governor isn't adjusted.
OP:
Reset the governor. It explains it in the manual. Please read it, and if you have any questions, just ask.
Here is the link to the Kohler K series manual on our site if you do not have a copy:
http://www.onlycubcadets.net/forum/s...ead.php?t=4646
I suspect that you also do not have the throttle cable attached properly. Disconnect the throttle cable. DO NOT allow the engine to over-rev as it can literally come apart. (As Austin stated) Also, DO NOT adjust the rod between the carb and the governor. Adjusting the governor accounts for the length of that rod. If you change the length of it, then you have to readjust the governor.
Unhook the throttle cable, do the governor adjustment, then report back.