There was no throttle control on the carburetor. All you could do was vary the needle valve setting.

Speed control accomplished through advance/retard of spark only.

The electric-start model had a tiller handle control that slid back and forth to change timing settings.

Best,
PM T2[/quote]

Some of the Speedsters on YouTube looked like they clipped right along.
I presumed "poppet valve" carbs with no throttle were only on little
outboards like my Thor. Interesting!