So I'm trying to revive an old schwinn varsity to ride around until i can save some dollars and buy a decent bike. Long story short, I cleaned and replaced everything that needed to be to make the bike rideable, but when I pedal the bike it feels like the brakes are being applied at about 75%. It's able to coast perfectly well so I'm pretty sure the problem is somewhere in the crank and not something else.
Working with bottom brackets is completely new to me so I dont really know where to start or what could be making it so difficult to pedal. I'm really itching to get this bike in working condition - the weather's getting nice and i dont have another bike to use so I would really appreciate any advice here

Thanks!
Adam