briggs & stratton 6.5 h.p lawn mower engine?

Depends wheather its a side valve or an over head valve engine, ohv engines will have a standard adjustable rocker arm, side valve engines valve adjustment is a dealer job ( grindind the end of the valve stems ), as it is very importent not to remove too much from the valve stem, as this will efect the de compression valve in the engine making starting very difficult, valve timing is done by the cam shaft ( aligning the dots on the cam and crank gears )this only ever needs doing after an engine rebuild.

Husqvarna man
January 2010