Another buddy of mine's got one of them Kohler 25hp gdlt. He say's to me--man my motor aint been runnin right! Alot of noise on the top end of the motor, I ask him when is the last time you checked the valve adjustment??? Never was the answer motor has over two hundred hour's on it!! I guess I will be setting valve clearance this weekend. Am I safe to guess .006 intake and .008 exhaust?? At top dead center or 1/4 past like a Briggzilla?

Nope.

Valve lash is set by a torque spec due to having hyd lifters. This spec is achieved when the lifters are bled down and by applying torque (with a torque wrench) to the rocker arm mounting bolt in the center. Is he running the mechanical fuel pump?

yes on the mechanical fuel pump