This a question regarding equity as calculated via the double your outs method and equilab.

This is the situation:

And I have pot odds of 25%

Now if I calculate my card equity

Double the outs: 8 * 2 = 16

Add one: 16 + 1 = 17%

= 17% chance of making the straight

By this method I shouldn't CALL - because pot odds are great than equity!

But if I put the above hand into Equilab my equity is 42%

So I should call! ?

Basically I'm most likely being dumb ... but what is going on here and what am I missing?

Thanks!