AKNick
640cc Uber Pimp
I'm guessing when you snap to inverted flat spin the throttle stick is at idle? You should consider an idle-up switch so the engine idles closer to 3000 rpms while flying. This will help it tolerate various tumbling moves a lot better.
I use an "idle up" on my 71 slick w/DLE35RA, 3DNater is spot on. I had the same issue, It didn't like pop-tops... Idle is around 1600-1800 and I my idle up is about 2400-2600. once again, spot on [MENTION=4]3dNater[/MENTION]
It isn't enough rpm to effect the way you fly. Just flip the switch once lined up on the runway for take off and flip it off during your decent back to the runway.
Some of these carbs don't have all the bells and whistles to supply constant fuel pressure through the full throttle range as 3DNater already said. If you are running a little rich, fuel will puddle up inside the card a bit - so when you do an aggressive maneuver it will give you a rich condition. My DLE35RA still does this a bit during its first flight before the engine/carb are warmed up. It used to bother me, now I just live with it.