chasing in limit

If you have a gutshot, a flush draw and second pair do you chase past the flop when the other guy obviously has top pair? I figure, with the number of outs, it makes sense to chase, but I ain't no pro.

If your chasing, then you should be drawing to the nuts (or near nuts)
is it nut flush draw (A) ?
is it nut str8 draw ?
if they are nut draws you have roughly 14/15 outs which gives you above 50% equity, (using 4 and 2 rule)
so I would probably raise here.
I am no expert, these are the first thoughts to come to mind so please
correct me if I am wrong