Here is my suggestion for an easy in-flight start of a cold engine on a trike with a Black Devil engine. My single seat microlight started easily enough but had a problem stopping several times during warm-up until the air was completely purged from the fuel system.
Alex Varv, as he usually does, provided me with a simple solution sending me the details of an in-tank fuel filter with a check valve. This check valve prevents the fuel from running back in the tank if the engine is stopped.
I soar with my trike and it is very important that the engine starts up even if cold.
In order to further improve things I replaced my fuel primer bulb with a real fuel primer that brings the fuel directly from the tank and injects it in the carburetor venturi.
The Walbro WB series carburetors do not have a choke and therefore I needed the push primer which is located in a very convenient and accessible spot on my trike.
My primer system should start the engine the first time after priming but each engine is different so one should experiment and learn how much to prime depending on the air temperatures, fuel, fuel mixture etc.
The primer doses the fuel very precisely and onece we learn how much to rpime, we will never flood the engine.