You mention setting the valves....you mean you just checked gap? Or lapped them and reground the ends? What were your guides like? My exhaust valve guides were very worn on 2 and a little less on the vk 30. Basically I used the valves and train of a vk30 the original block an piston and the crank and lower housing of another. Chucked the zenith and rebulit the Walbro. New rings gaskets and lower seal and a new c starter cup and she runs like a dream. The only thing I hate about this carb is the primer it makes a puddle on the base with no run off hole and running down the whole side of the mower leaving a mess, so im gonna modify the bowl and use a sealed nipple and dran tube. Agreed with grumpy the best part of this engine seemed to be piston and wear was minimal on all 3 with the exception of a dropped ring groove rendering one useless.
