Weak Turn?

[imported_ncray]

Party Poker 2/4 Hold'em (7 handed) converter

Preflop: Hero is BB with 9[img]/images/graemlins/spade.gif[/img], 9[img]/images/graemlins/club.gif[/img].
<font color="#666666">1 fold</font>, MP1 calls, <font color="#666666">1 fold</font>, CO calls, Button calls, <font color="#666666">1 fold</font>, <font color="#CC3333">Hero raises</font>, MP1 calls, CO calls, Button calls.

Flop: (8.50 SB) 6[img]/images/graemlins/heart.gif[/img], T[img]/images/graemlins/spade.gif[/img], 2[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(4 players)</font>
<font color="#CC3333">Hero bets</font>, MP1 calls, CO calls, Button calls.

Turn: (6.25 BB) K[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(4 players)</font>
Hero checks, MP1 checks, <font color="#CC3333">CO bets</font>, <font color="#CC3333">Button raises</font>, Hero folds, MP1 folds, <font color="#CC3333">CO 3-bets</font>, Button calls.

River: (12.25 BB) 8[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">CO bets</font>, <font color="#CC3333">Button raises</font>, <font color="#CC3333">CO 3-bets</font>, Button calls.

Final Pot: 18.25 BB


CO is fishy. Button is laggy.
Is the turn check weak? On the uncoordinated board I figured callers had overs or some sort of a pair. The king hit, completing an "over draw." I can gauge the action behind me with a check, planning to fold of course to a bet and a raise. I'd also fold to an early bet with overcallers. What's my plan though if I check and it goes bet fold fold? I'm thinking fold behind since they would be betting into a protected pot. Any variations where you would call? Should I just bet the turn outright?