I agree all engines benefit from a proper break in, however, the magnums can too be flown "right out of the box." I have never seen one that will not work! And I'm at a high altitude>5,280ft plus. That goes for both 2 and 4 cycles.
Point the airplane up to see if it leans out, and check that the throttle transition is smooth, if all is good, fly it, you won't be dissapointed. If not, adjust it, I've never had one fail me yet.
Just realize the possibilty of a dead stick because the engine isn't broken in yet.
The magnum is on top with the best of them with regards to power and reliability. :boxing: