I just don't think he has an ace ... how to play it?

Villian is 26/13/2. My image is not solid at all, as I've been caught bluffing twice recently. Check on the river was to induce a bluff and save money if I am behind a weak ace or a K.

Party Poker 30/60 Hold'em (10 handed) FTR converter on zerodivide.cx

Preflop: Hero is BB with J[img]/images/graemlins/heart.gif[/img], 6[img]/images/graemlins/diamond.gif[/img]. CO posts a blind of $15.
<font color="#666666">6 folds</font>, CO (poster) checks, <font color="#666666">1 fold</font>, SB completes, Hero checks.

Flop: (3 SB) 3[img]/images/graemlins/diamond.gif[/img], A[img]/images/graemlins/diamond.gif[/img], 6[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
SB checks, Hero checks, <font color="#CC3333">CO bets</font>, SB folds, <font color="#CC3333">Hero raises</font>, CO calls.

Turn: (3.50 BB) K[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, CO calls.

River: (5.50 BB) 7[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, CO checks.

Final Pot: 5.50 BB

Comments on all streets welcome.