Okay, I took this engine off my plane and back apart to show what I did to it back when we got our first shipment of engines, when I did this it was not because it died when it was tilted, never noticed that but it may have. It was obvious to me through the ground running and tuning I did that there was fuel puddling next to the reeds. It's possible that a nipple with a check valve in it or in line to another nipple in the crankcase may do the same thing, outboards use the same thing to prevent pooled oil from loading up in them as well. They use the pooled oil routed through check valves to lubricate the crankshaft bearings. Anyway here are some pictures, one of a new un-touched crankcase back, then the modified one. If this is attempted I must stress caution, the case is not very thick and can easily be ruined by grinding all the way through, it was done by hand with an 1/8" ball mill and then the edges were smoothed more with a fine file, enjoy.