Start over and Back it and jack it are 2 different things and not really the same as OP was talking about.
Another weird one from the past few years.
The phrase in all the pool halls I have ever been around was always 'run it back', meaning run back the coins, beads, or whatever score keeping method you are using, to zero.
As in:
2 players on the hill, one suggests running it back. That means starting a second set for the bet wagered on the first set AND another bet on the second set.
Gives both players a chance to win 2 bets, instead of seesawing till you break even.
Back it and jack it sounds like shit one of the goofballs at a convenience store says while asking for "Marbs" instead of Marlboros.