Cylinder 3 misfire at low revs

[His Dudeness]

In general if you're trying to work out what jet does what you can often follow the casting in the body of the carb. Trace down from the jet to the body of the carb. There's often a raised section in the body of the carb where they've drilled to create a passageway. If you follow that it will show where the jet is going. Once you know where the jet is going you can spray some carb cleaner into the jet and watch does it come out where you are expecting it to. If it doesn't then there's a blockage somewhere