There is such wisdom in this thread. I do think it is normal for teenagers, especially but not only boys, to long for free time more than for school time. They are getting older and experiencing exactly what we adults know and hold to be true... there is not enough time to do everything we want to do... and we sometimes wonder where they time went and wish we could find more time in the day. Prioritizing is something that maturing teenagers begin to see the need for. They don't know how to do it at first, and sometimes even as an adult I'M not that good at it myself.

There are things that have to be done, and things that we want to do. The 'have-to's' have to take precedence over the 'want-to's'. It's a tough lesson to learn. As our very active, outdoor loving teenage son would probably always choose active outdoor things (or wild wrestling type things indoors

) rather than more sedentary school things, we have the understanding that 'x' amount of school must be done before he does 'y' other things, and if there is a break he needs to be grown up enough to come back and finish, or there will be no break.
I do think the order of the day can make a difference. My almost 14 yo is an early morning guy, so he gets up at 6 AM and does some of his independent work for his WG in his room. I told him the subjects to do within that time frame, and I based it on the most independent things he can be successful at doing in his bedroom. From 7:30 to 9 AM, he showers, gets his room in order, does his outdoor/indoor chores, and often times, chooses to make breakfast for fun. He loves the outdoors and he loves to cook, so these are two great ways for him to begin his day downstairs. After that, I meet first with him and go over his dictation, grammar, and math, as well as have him show me his subjects from his room time earlier. We have hot cocoa with whipped cream during our meeting times, or hot tea, and the other dc are playing together upstairs, so it's a grown-up private kind of meeting time together. This lasts about an hour. After that, he works until 12:30 PM and within that work time he can get himself a snack. At 12:30 PM we have lunch. Then, he finishes from 1 to 2 PM, and within that time I check the rest of his work and finish out anything I need to for my part in his plans. I have control of the meeting time, and I always have him do the same subjects and check his previous work. He has control of the order of the rest of his subjects, the order he does them in that is. He must work until he is done. Then, whenever he is done, usually the other 2 dc are done, and it's 2 PM, and they head outside for an hour to blow off some steam together. He works 2 afternoons a week at 2 PM though, and on those days he comes home more around 3:30 PM and heads outside then. His late afternoons and evenings are mainly free, though he often works on projects with me or my dh, and we like to play card games or watch football right now. He is also an avid reader and enjoys his room time later at night. Usually he heads upstairs with brothers around 9 PM, and lights out at 9:30 PM. I do think enough sleep is important at this age too.
We have had the talk that school is like his 'job' right now, and it is providing important training for having a job as a grown man in the future. His dad has explained that he doesn't get to just stop his work when he doesn't feel like it, or only do the parts he loves, or mess around in the middle of it. He wants to be like his dad, so this was a motivating talk. He is a hard worker and he does take pride in and enjoy his school overall, but honestly, his hard work in school is just as much about him equating finishing his school work to earn free time.
I hope something here can help, but I think I'd talk to him about becoming a man, working hard, plan a few breaks, but I'd not let him just decide to go play or wander off whenever he feels like it. Those days are done - he is older now and has more important work to do. I think if he equates finishing with free time, and knows he won't get much of it until he's done, he'll 'man up.'

Hope something here helps!!!
In Christ,
Julie