Sounds to me like you have a K-Series engine. Go to Kohler's website. Use the link below
Go to Section 3 Page 5 and you will that there are three engines with the 9 bolt pattern. K241, K301 and K 321. They are 10, 12 and 14 HP respectively.
In order to tell the difference, you would need to remove the head and measure the bore and stroke so you can compare it to the chart in that manual.