Thanks Dave, I was thinking about another thread, it appears (or I was completely confused). The Suffolk will probably idle considerably slower than a Briggs. I think you have now got the idea of stopping and starting the forward movement of the mower with the hand-clutch. The centrifugal clutch stops everything (reel and roller) but is not a safe way to park the mower: you need the hand clutch on the roller drive to fully disengage when you release it. Then the worst thing that can happen when it's sitting there idling is that the reel spins up from time to time, but the mower doesn't move.
I seem to have seen video of an English mower with a centrifugal clutch like yours. The reel sometimes stopped when the engine was idling, and sometimes didn't. It might be a feature of only marginal effectiveness.
