Hi Ted
I remember the little 909 green mowers as well. From memory, the one I saw didn't have a throttle adjustment - just a spring about the same as a mech governor one but on a little peg. Start it and it ran at 3000rpm - on or off.
I immediately thought it had an airvane, but never looked further.
Only time I have ever seen a similar set up is american mowers or rovers for a few years
