I don’t understand why threads like this get resurrected with responses that are 10+ years old. Most if not all of the people involved in it are long gone from the forum.

As far as the actual thread topic having any relevance - not really. People that seal their engines to eliminate (phantom) “air leaks” don’t understand that these engines rarely leak! If they do, there will be witness marks of oil seeping out where the leak is. The only place RTV can be beneficial is below the carburetor fit the o-ring is dried out or missing. Otherwise sealing the backplate, head, etc. is pointless. Especially if the backplate is sealed with an o-ring. If your engine doesn’t run right, 99% of the time it’s improperly tuned. Tips for proper tuning in order of Importance:

Carburetor idle gap set to 0.5-0.8mm. New engines being broken in may need the idle gap as large as 1mm for the first couple tanks of fuel.

Proper heat range of glow plug for the fuel being used. 0-10% nitro a hot plug is suitable; 15-20% nitro should use a medium heat plug. The colder the plug, the sharper you can tune the fuel mixture and make a little more power. The consequence can be a lowered idle quality - less heat is retained in colder plugs, so they may blubber a bit off idle. If the needle is set correctly, this is rarely a problem though.

Proper tuning sequence and needle settings. Set the high speed needle for best performance first, then back off 1/16th-1/8th turn richer. Idle mixture set for a steady idle that is low and slightly rich so after a 10-15 second idle period the engine is ever so slightly loaded up. This ensures after a hard run there is enough fuel to cool the plug down. If it’s too lean, often the engine will suffer from “idle hang” where the rpm doesn’t drop immediately when throttle is reduced.