Prop suggestions

[winter sux]

I have a 17.5ft bowrider with a 140 3L the boat only weights 1500 - 2000lbs what prop size should I go with to get the most out of the engine. I know I should try other props sizes but I am looking for a starting point. I just got this thing in Oct only had it in the water a few times it moves pretty good now but the prop is a little beat up and I thought it being winter I might find a deal on a prop.

Thanks Jeremy