20/40 turn decision with top pair

[Mr. T]

20/40 live. Most of the table is loose weak, CO is a little loose and a little tricky but nothing special. In a previous hand against him where I raised pre flop and on the flop he then donked a non scary turn with middle pair and no other draw.

I'm the BB with Q [img]/images/graemlins/diamond.gif[/img]J [img]/images/graemlins/diamond.gif[/img], three limpers, SB calls, I check.

How often should I raise this preflop?

Flop: Q [img]/images/graemlins/spade.gif[/img]6 [img]/images/graemlins/spade.gif[/img]8 [img]/images/graemlins/club.gif[/img]
SB checks, I bet, 2 calls, CO raises, Sb folds, I 3-bet, only CO calls.

Turn: 7 [img]/images/graemlins/spade.gif[/img]
I bet, CO raises, I...