Just like people, I guess all puppies/dogs are different. Tucker will be 16 weeks on Saturday and he holds his pee all night. We take him at 11 pm before we go to bed and then he barks around 6-6:15 am ready to go potty (and then play like a wild man).
Since you are attempting to take him outside and he doesn't go potty, but does inside, it sounds like he just hasn't figured out that outside is the correct place to do his business. It defintely helps to get in a routine so they know to expect you to take them and what worked for me was buying some really high quality treats that Tucker only gets after he goes outside to potty. He's learned this, so now sometimes he'll go potty, get a good treat and then 10 minutes later, he'll want to go out again (because he wants more treats!). If he manages to squeeze out some more pee, I give him another treat cause I"m a pushover
We also praise him like crazy - I clap and make a huge deal after he goes potty outside. He trots around, so proud of himself when we do this. On the other hand, when he had some accidents I didn't yell or anything, but I did talk in a deep voice and let him know that was not ok and then took him outside to show him the correct place to go - but given this is only effective if you catch them in the act.
I know this probably wont' work with everyone, but just letting you know what worked for me! Hope this helps!