should i have pushed AK?

[meleader2]

Ultimate Bet No-Limit Hold'em, $.50 BB (8 handed)


BB ($34.50)
UTG ($7.20)
UTG+1 ($38.05)
MP1 ($12.15)
Hero ($47.70)
CO ($24.35)
Button ($36.65)
SB ($36.80)

Preflop: Hero is MP2 with A[img]/images/graemlins/diamond.gif[/img], K[img]/images/graemlins/club.gif[/img].
UTG+1 calls $0.50, <font color="#666666">1 fold</font>, <font color="#CC3333">Hero raises to $1.5</font>, <font color="#666666">5 folds</font>, UTG+1 calls $1.

Flop: ($3.75) 8[img]/images/graemlins/diamond.gif[/img], 9[img]/images/graemlins/spade.gif[/img], 8[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
UTG+1 checks, <font color="#CC3333">Hero bets $2</font>, UTG+1 calls $2.

Turn: ($7.75) 6[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
UTG+1 checks, Hero checks.

River: ($7.75) T[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">CO bets $20</font>, Hero folds, UTG+1 folds.

Final Pot: $27.75


ok i pushed AK on the flop
but CO hesitated and then called, then checked the turn. should i have pushed on the turn to see if he was on those spades??

at the river he did the classic stall bet huge which made me think he was on a boat. any thoughts??