The OS carbs can't be converted, but some carbs can be. Magnum RNV carbs, for example, can be converted easily to "normal" operation.

You can buy older-style OS carbs that will fit, or other makes of carbs if you really want to.

That said, I haven't had any problems with my RNV engines, and I've seen a lot of guys flying them with no problems at all. I haven't seen air in the line between the RNV and carb, so I suspect you have an air leak somewhere. And an RNV carb will act exactly like a normal carb with an air leak, all kinds of things won't work right. Find the leak, and you should be ok.

fwiw, I don't care much for RNV either, I converted all my Mags to normal operation, and would convert my OSs as well, but it's too much trouble, and they do run fine for me.