Dave, I dont personally use any sealant. Just a little grease to hold it in position until and secure the engine head. I have never had a problem with this method. Be careful no to overtighten them as you will blow the gasket easily. When the gaskets blow in my experience the engines dont normally start because of the lack of compression.
I am still leaning towards a carby issue. I trust you cleaned the carby with compressed air properly? Some pictures of your mower and carby will help us get a resolution. Did you replace the float needle, whenever I overall a victa 2 stroke I always replace the needle because they can cause havoc with correct fuel flow. The tip of the needle might seem ok but I have found many mowers that only needed new needles.
Victorius, can you start a new thread on your problem to avoid confusion with Dave's thread. I am happy to help and Im sure others will too.
Peter
