Rope length on an I/O

Sup fellas, Ive really started hittin this sport hard this year, I figured everything out pretty good, except, I see that all these postings sayin that thier ropes are 75 and stuff, but my boat's (VIP I/O 175hp) wake starts to roll way b4 that, am I doing somethin wrong, do I jus need to adjust my lenghth real short, and if my rope is short is that ok? Thanks