I don't have any problems with the orings. The triangle shaped piece are screwed together with the crankcase with three screws and there is also three extra holes near the shaft. There is no leakage from this instead it's the extra three holes that the heater that you say in your pictures where screw in. First I could manage to nearly start it if I flooded the carburettor and the fuel where spitted out of these extra three holes but later after I fixed that problem the engine where drawing fuel like it should do but now I think it's to much fuel.

I'm on holiday from Sunday to Sunday so with in two weeks I can start checking this things again.