“whenever the ENGINE CONTROL switch is in the START position or in either of the two RUN positions.”
The Prime & Run position is the same as the Prime & Run with the addition of the Aux Fuel position in terms of functionality.
30 years ago, when this generator was designed, people understood and reasoned and applied logic differently then today.
The understanding that common sense should prevail was implied.
The internet was in its infancy, people used 14.4K modems for dial up AOL chat, no one knew what a iPhone, iPad, Android, WiFi, YouTube, facebook, instagram, TikTok, eBay, Amazon etc etc was.
In those days, at least in Germany, technicians knew they had to read the entire section of the manual to understand its functionality to properly troubleshoot the apparatus.