help with rossi engine

hi had to completly dissasemble the carb and lost the settings
this is my first rossi verry powerfull high compression eng.
i'm close to finding it but the fuel still foams so when i'm at 1/8 of fuel left it's to foamy and leans itself.i'm sure it the carburator since it was realy bad at first and now it's way better.
i have 1 1/2 low speed and 3 high speed,
a buddy told me to had the extra shim in the head and that this would smooth it out.
if someone thinks of anny thing else that could fix this please
feel free to suggest annything.you never know it might work

manny thanks in advance

steff