Weak KK play?

This is a step-higher tourney with 8 people left and basically 2-7 win their money back and the winner advances to the next level. I thought I should test with $150 after the flop but I thought it was probably 80% that he had an ace and just checked ready to fold to any decent bet since I had an average stack and it was so early. Big mistake?

30/60 Tourney Texas Hold'em Game Table (NL) (Tournament 14948663) - Thu Aug 18 15:28:56 EDT 2005
Table Step Higher 1 1032420 (Real Money) -- Seat 8 is the button
Total number of players : 8
Seat 1: Sluffers (705)
Seat 2: carlblasbery (665)
Seat 3: Mach73 (1050)
Seat 4: deric (890)
Seat 6: andy_fish (905)
Seat 8: grunt11b40 (965)
Seat 9: beakjob (2370)
Seat 10: WOWED74 (450)
beakjob posts small blind (15)
WOWED74 posts big blind (30)
** Dealing down cards **
Dealt to andy_fish [ Kh, Kd ]
Sluffers folds.
carlblasbery folds.
Mach73 folds.
deric folds.
andy_fish raises (100) to 100
grunt11b40 calls (100)
beakjob folds.
WOWED74 folds.
** Dealing Flop ** : [ Qd, Ac, 9c ]
andy_fish checks.
grunt11b40 bets (225)
andy_fish folds.
** Summary **
Main Pot: 470
Board: [ Qd Ac 9c ]
Sluffers balance 705, didn't bet (folded)
carlblasbery balance 665, didn't bet (folded)
Mach73 balance 1050, didn't bet (folded)
deric balance 890, didn't bet (folded)
andy_fish balance 805, lost 100 (folded)
grunt11b40 balance 1110, bet 325, collected 470, net +145
beakjob balance 2355, lost 15 (folded)
WOWED74 balance 420, lost 30 (folded)

[unreal_nh]

unless u have a great read on the player, its probably a good fold

that's how I'd play it.

[adanthar]

You played the hand OK, solely because in that particular tournament you want to go for the freeroll first, but...

[ QUOTE ]
I thought it was probably 80% that he had an ace

[/ QUOTE ]

wrong

[kyro]

If you check the flop, you really need to fold as the prize structure increases dramatically from 8th to 7th. However, I bet out on this flop and hope to his pocket pair folds. If he calls and I brick the turn, I'm done.

You think it was closer to 50% or less? Thinking out loud I have no read but even assume he is fairly loose and he has position...possible calling hands would have probably been 77-KK, ATs, AJ-AK, AA. I guess you are right.