The 82 will spin a 14x4w just fine on 15%, I use that combo on mine. I do have to second the above comment that the OS 55AX is also outstanding, especially with the Tower muffler that will give you a few hundred extra RPM's for $14.99. The big advantage of the 55 AX is that it just sips fuel compared to my 82, roughly twice the flying time on the same size tank of fuel. I'm finishing up my PRIMO this week and already have the 55 waiting on my bench to be installed!

Tim