actually i was thinking of the e-60 which has a drop adjustment screw. figured the e-47 would have one too... if you go to angelos supplies website there are meyers troubleshooting guides that deal with this problem for the e-47
Very posible that the piston cup seal is gone allowing the fluid the bleed over and back to the tank.
You will need to take the top part of the unit apart and remove the piston and cylinder to check the cup, and will require a few other seals to put the unit back together so don't do it unless you have all the parts on hand.
Garage keeper hit it on the head, you need to rebuild your lift cylinder you will need a master seal kit, If your pump is doing this now your best bet would be to redo the whole pump while you have it apart, cause if there is a piece of dirt or something which could have ripped the seal is most likely still in there and will cause failure again, also if the seal just went bad then the others might not be far behind. Also did your lift ram have rust on it and you ran it up and down without using some 300 grit paper to remove the rust, that usually causes a problem like this.
MAster seal Kit is about $55.00 Make sure you get a Meyers one and not an aftermarket one. not all the seals are exact in an aftermarket one (speaking from experience) You should always use original parts they may cost a few bucks more but at least you know there gonna be right!