Hi Andy:

Cap it. Your opponent is displaying maniacal tendencies. The most logical hand to put him on here is a slowplayed set that wakes up on the turn. You don't fear the backdoor flush unless he has exactly Q [img]/images/graemlins/heart.gif[/img] J [img]/images/graemlins/heart.gif[/img] for a two pair that came alive on the turn. Cap it, and expect to set a poorly played set lose to your straight here 90 % of the time.

Btw, I agree with most other's line here that you need to get more action on the turn. (pretending I don't know you posted results yet...) Villain might have gotten lucky and turned his weak ace into a boat, but you probably want to cap on the river. Put in more action on the turn and define your hand a bit, so you have a better idea of what a river 3-bet from him actually means.