KK Confusion

UTG+1 is 18/14.6/3.27 over 180 hands. MP3 is posting his first hand and unknown.

Preflop and flop standard?

I got real confused on the turn and checked. Too weak? How often am I ahead here? How often do I need to be ahead here to justify a bet, given the 10 (discount of 1) outs if I am behind?

Party Poker 5/10 Hold'em (10 handed) FTR converter on zerodivide.cx

Preflop: Hero is CO with K[img]/images/graemlins/spade.gif[/img], K[img]/images/graemlins/club.gif[/img]. MP3 posts a blind of $5.
<font color="#666666">1 fold</font>, <font color="#CC3333">UTG+1 raises</font>, <font color="#666666">3 folds</font>, MP3 (poster) calls, <font color="#CC3333">Hero 3-bets</font>, <font color="#666666">3 folds</font>, <font color="#CC3333">UTG+1 caps</font>, MP3 calls, Hero calls.

Flop: (13.40 SB) J[img]/images/graemlins/club.gif[/img], 6[img]/images/graemlins/diamond.gif[/img], 4[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
<font color="#CC3333">UTG+1 bets</font>, MP3 calls, <font color="#CC3333">Hero raises</font>, <font color="#CC3333">UTG+1 3-bets</font>, <font color="#CC3333">MP3 caps</font>, Hero calls, UTG+1 calls.

Turn: (12.70 BB) 7[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
UTG+1 checks, MP3 checks, Hero checks.

Thanks,
Andrew