The jabiru 2200 uses a bing 54 carb. The nominal pressure for them is 1-4 psi. They need to be fed, but anything over 4 psi can cause the carb to flood.
he probably didn’t install the facet filter because they aren’t serviceable and was relying on the main filter.
The bypass isn’t always a well known thing and more of a work around to avoid failure. Theoretically the facet pump should allow flow through. Just sucks to find out that one time it won’t or that it’s causing a bit to much restriction when it’s not running.
Tom Yoder