They all have governors, with or without a speed control. Its true the engine will be most efficient at a set rpm for under load but by setting a control to full, the governor will maintain that "pre-set rpm". The governor doesn't increase rpm, it increases throttle under load to maintain rpm.
The factory and sales folks are just feeding a bunch of BS, the real reason most units no longer have a throttle control is to save money by eliminating those parts needed to have them. Governors will always be on them because they are needed. The last engine without a governor was a Tecumseh built only for Sears as a low cost engine, back in the 70's. To prevent over revving they set the cam gear one tooth off so it ran to crappy to over rev.
Nevada! The last free state!
Retired Briggs MST, Honda Top Tech.
Currently full time experienced novice fisherman.
You should've been here yesterday, the fish were really biting..