Lucky 7 Rc Engine Sealant for nitro engines is a quick dry air seal which doesn’t require engine to be disassembled. If your nitro engine has an air leak around the neck of the carburetor, or the needle valve assembly, it can make the engine run inconsistent.  To avoid this, it is a good idea to seal the carburetor around the neck and needle valve assembly, and this sealant works great.  You can also use it to seal the engine’s backplate.