Here is a picture of the location of the Fuel air mixture screw. Screw in until it just seats. Do not put extra pressure, just as it seats stop. Then turn OUT of 2.5 turns is recommended from the point of seat.
Of the 4 screws to the cover of the diaphram, locate the bottom 2. Pick a point about 1/2 the distance of the 2 screws. Then directly below that point about 1/2 inch you will see a hole and there is a screw inside.
If yours is solid like mine were, then you will want to carfully drill it out.
I believe there are some members that know the exact drill side and how much to drill in to uncover the opening. Maybe you are lucky and yours is already accessible.