First, you should be accurately reporting the hours you work. Depending on where you work, falsifying a timesheet (even if you're underreporting) could be illegal, and if nothing else you're currently not giving the company an accurate picture of what you spend your day doing.

You shouldn't go to your manager and just say you don't like this work. Everyone has to do some stuff they don't like doing, and the response will probably be "Too bad." What you should do is tell him that you're concerned about your ability to give your best effort towards productive work on the project when you're spending so much time training new people.

If you start accurately reporting your hours, even if you're salaried exempt, you can point to these reports and say "I spent X hours per week doing training over this time period, which lead me to do Y hours of overtime. I appreciate the trust you've shown in me with this added responsibility, but I'm concerned about how these extra tasks are affecting my productivity on the project. Is it possible to get someone else to help out with training new recruits?" However, if your timesheet shows that you're getting all your work done in the normal number of hours, your manager will probably ask why the timesheet says one thing and you're telling him another.

Also, this is based off the assumption that you're okay with doing the work, but it's just taking up too much time. If you're actually just uncomfortable with training people period, that's a different discussion that needs to be had, but it will probably have implications for your future and advancement within the company if you're unwilling to take on this kind of added responsibility.