I have the same motor in my trainer and just like you, bought it new and it sat in the box for 4-5 years before I started it. checked over good, mounted it, fueled up and it popped right off with a hobbico starter. a few adjustments later I had it idling fine and the run up was smooth and steady. .....good engine. it is designed to fit where a typical .40 size engine would fit, so you shouldn't have any problem.