THe reason I think he wants a centrifugal clutch is that he thinks it works like so (My impression):
When the engine is at idle, the clutch is shrunk down and does not transmit any power, just spins happily away. When the engine speeds up a bit, the clutch fans out and contacts the SIDES of the clutch, grabbing on and driving the wheels at whatever speed the engine is moving.
Or something like that.
He wands a way for the starter to engage only when it's needed.
That's only what I think he wants. I could be very wrong.