My 2002 Merc 40 2-stroke is having a tough time starting if the engine is left, not running, tilted up for any time. This is a real pain as I don't like to trailer the boat with the engine straight down. If I ride to the ramp with it up, I'll have to wait a full 30 minutes before I can get her started once the engine is straight down. If I trim it up while running, it runs fine. But if I leave it up while fishing then try to start it, it won't start. If I leave it straight down for 10 more minutes, I can get it to start. Gas line is not pinched in the tilt position. Any ideas?