Laurie, it would be good to plug the hole in the bottom of the float bowl temporarily so you can verify that the solenoid is not implicated: I've read that it often ends up with reduced armature movement even though it still moves. Also, you've checked that the solenoid's armature moves when you put 12 volts on it, but you haven't checked that it gets 12 volts when you turn on the ignition. This needs to be cleared up before going further.
Next question is, when you removed the solenoid, did a float-bowl-full of petrol run out all over your hand? If not, you have a problem either with the fuel tap (like, you left it turned off and that is the problem) or with the needle-and-seat (stuck or blocked). If the float bowl was full, we'll need to get into the gizzards of your carburetor, so we need a picture of it please, along with your engine model number.
Last edited by grumpy; 31/12/10 10:28 AM. Reason: Clarify solenoid situation.