RE: NGH 9cc
Tovarish Evgeny as I can see you are also using some kind of return line on fuel line as I recommend.
If you mean your engine s lifespan,I know those engines as JBA 56 glow blocks.If you dont damage the conrod you can be sure piston and liner will serve you much more than you expected.I recommend you to check spark timing to stay safe side to keep conrod in good shape.