spray air intake with gasoline before start

i need your expertise to help me to find out what is the problem with my van a
1996 savana 350 vortex engine and has only 43189 kilo. the problem started when
i filled it up with husky gasoline and stored last winter. i never had a problem till
last march 2010  when the van did not start in the morning it seem that there is no
enough gasoline going to the fuel system.i have to sprayed gasoline through air
intake before the van start.and run flawless during the remainder of the day with no
problem in starting. so every morning i have to remove the filter cover just to
sprayed the air intake and the van start. i am just wondering what seems to be the
problem. thank you