Teddy.......when you re-polarize you create and "arc-spark" between the the side-by-side BAT and ARM terminals of the 8N squarecan voltage regulator. After all you are SHORTING the BAT to GROUND thru the ARM. And you are "magnetizing" both the genny soft iron core and the ironcore of the cut-out relay inside the squarecan voltage regulator.
You magnetize the iron core of the cut-out relay so it will disconnect when you turn the engine OFF.
It is always recommended to re-polarize ennytime you replace the battery. Why? 'cuz many shadetree mechanics erroneously install the 6-volt battery as negative ground like their 12-volt Belchmobile-V8 with alternator.
Wannna guess what incorrect genny polarity will do to new battery???
Surprizingly enuff gennys don't care positive or negative ground. There are some obscure technical reasons for positive ground (hazzta do with electron attraction of arcing sparkplugs) Modern sparkie material and design have negated that technical advantage.
As I said, you can re-polarize as many times as it takes to feel warm and fuzzy ...er... charging .......Dell