Hi Randell,
Poppet valve should be set to C unless your mower is a vortex.
When you say 70% do you mean it runs at the same RPM irrespective of throttle position or do you mean when you take it to full throttle it revs up momentarily and then drops back the RPM by itself.
If it does the latter that is normal but a picture of the mower will help as the earlier ones are a little different to the later models.
