the problem with calling is that the flush draw is more bad than good. I either call playing it as basically only a straight draw or reraise trying to get that other flush draw the heck out and taking on the SB headsup in which you're almost even (including the two dead spades).
It's not automatic one of them has a flush draw however.

Problem 2 is if you hit that flush it's harder to get it paid off when it's the best hand.