Left engine: Thicker smoke trail AND hotter? Well...that's a new one to me. I'd guesstimate either bad fuel, an exhaust leak somewhere(This would cause piss-poor fuel pressure in that engine's tank, which would cause it to run funny), a pinhole leak in the fuel line, cracked tank or perhaps an air leak on the engine itself.


Right engine: Check the plug and make sure that is good. Break in is notorious for munching plugs, and usually when an engine cuts out and it's not an air or fuel issue it's a bad plug. Could also be bad fuel, I'm assuming you're running the same stuff through both engines.