[embee]

Everything says sticking choke plunger.

To do the front one you really need to remove the carbs, it's not impossible without but near enough.

If the retaining screw won't shift (likely) first add penetrating oil, second put a crosshead screwdriver/bit in the screw and tap gently with a small hammer. Make sure it is the correct crosshead (aka phillips) bit, not a pozidrive (crosshead/phillips is a plain cross, pozidrive has extra nibs in the corners, and the angles are different so don't fit the wrong screw heads).

It's best to use a bit in a socket set wrench if possible, usually easier to get good purchase on the screw without it chewing. If it does start to chew up, gently tap the screwhead back down with the hammer and tap the bit back into the recess to reform the cross.

Lube the cable and plungers. It's common to see white crusty corrosion where the cable meets the plunger.