The reason your plate was so soft after the first push of the plate,is because you have fuel in the chamber both upper and lower of the fuel distribution block,once you pushed the plate down you removed a large amount of fuel from the system,so now you have less resistance in the chambers.That fuel is what gave you the hard feeling when you depressed the plate,start it up and retry you will see it got harder again.JNT
The trouble maybe with the Orings on the center shaft or the metering rod look up rebuild of the fuel distribution block this is most likely Ware your fuel drip is coming from.take the system apart and clean up all that sticky junk and reinstall the parts!