It is a 10HP limit and no, you cannot idle your big motor, but it is small enough to use a trolling motor. That's what I do when I go there. You dont need a topo map of the lake, it's nothing but a soup bowl anyway. Any map you would find probably wouldnt be too accurate. There are some big fish in there, took 22lbs to win one of our club tourneys there this year (6 fish limit). Last year saw a guy weigh 4 fish for 18 and some change. I know for sure there is one 7lber swimming in there, I turned her back.