A little off won't hurt anything but it sounds more like a linkage problem rather than tuning. Adjust the length to get things to open right. Leaving a butterfly partially closed is akin to opening the slide barrel in a glow carb only a little bit and expecting full power.

Every gas engine from Ralph is tuned for performance at his location, which is about 4,000' (+/-) above sea level. It should go without saying that each engine should also be re-tuned for the final location it will be used at, by the owner.