idle enricher question

[dozerdoodle]

1988 mariner 75 3cyl., seems that fuel will only flow through enricher when engine is level " vertical" i was killing myself trying to get her started cold on trailer with engine tilted about a quarter way to flush motor. pulled hose off from carb, nothing came out till motor tilted almost all the way down. i blew on hose and air came out carb vent so i don't think it's clogged. is this how they are designed, i though maybe manifold vecuum would pull the gas through the line but appears it relies on gravity? i'm baffled because it looks like the hose going up to the top cylinder is higher than the solenoid, so how does it get the extra gas to start?