Did I misplay the nuts when I had them?

[wpr101]

Hi, I'm hoping to get some opinions on a hand I played in a $20 SNG recently. I had Ac9c. There were two limpers in front of me and I called also. I had last position and there were two other people in the hand. So the flop comes 4c 8c 10c. I hit the nut flush. At this point the pot is about 100. The first guy leads out for 100, the second guy calls, and I also just call. The turn then comes Kc and it gets checked around.

Did I make a mistake here giving a free card? I have the nuts at this point so should I make a bet? If so, what percentage of the pot should it be?

Anyways river comes 4s (there are 2 4's out there now). First guy bets about 50% of pot, the 2nd guy folds. I minraise; he re-raises all in, and I call. He had pocket 8's so his full house beat my flush.

I think my play on the flop was fine and I was hoping they would bet again on the turn but they didn't. Should I have bet that turn?