The 40FSR is a ringed engine so it might be best to assume it's never been run. That means running it very rich for some time so you won't be able to tune the carb anyway. In the meantime it wouldn't hurt to check out the carb to see if there's anything wrong with it. I'd also use a different fuel to run it in with. For one thing, why use expensive 15% fuel on a test stand for an hour? The other thing is that I believe (and correct me if I'm wrong) that Byron mix by weight so your 18% oil is actually more like 16%, far too little.