Tuning Gen 2 Marauder leaks.

So my Mrod which help air perfectly has started to leak while I gave it a 1 month vacation. I checked the charge port and gauge and found no leaks. It goes from 2000 psi to 1000 psi overnight. I have shot it several times and checked it with the rifle uncocked as well as cocked overnight with the same results. I was wondering if anyone knows of a way to test to see if the poppet is leaking without disassembling. If it is the poppet I will take it to a service center but if simply an oring I will repair myself. It is still under warranty but I don't really want to send it to Crosman or make 4 trips 50 minutes long to the service center. I thought maybe if I removed the shroud and baffles and closed the bolt I could put a piece of tape over the barrel end and put a pin hole in the tape to see if any air escapes there. Any thoughts????
 
Oops assuming you used soapy water at the manometer threads already and found no bubbles to indicate leak and if you already put a rubber banded held balloon or condom (clean one of course) over the barrel and it didn't fill up with air then it's not your valve or poppet.

If the other balloon or condom rubber banded to her the fill connector doesn't fill up either then it's your manometer threads leaking then you yellow Teflon tape to seal it as above.

Manometer threads leaking is usually first thing that leaks for Benjamin PCPs.
 
Thanks for the input guys. I pulled the scope and receiver and submerged it while pumped up to 2800. I did one end at a time and found nothing on the receiver end however a bubble about the size of a bb escaped the charge port about once a minute so I will check that out. I remember right before I switched from squirrel hunting to bow hunting I topped it off and forgot to put the cap back on. I hunted that way and used compressed air to blow it out before charging but maybe some dirt got into it. Thanks again. I will keep you posted tomorrow.
 
OK guys thanks for all the suggestions. The culprit was the fill port. I degassed the gun and removed the fill port assembly and tapped it and shook it to make sure all was free inside. After this I took 100 psi air and blew it out while shaking it. I reassembled last night and charged to 2300psi. This morning it was still 2300 so for now all is well. I originally was going to take it apart but figured I would try this and then order both the fill port valve as well as the parts needed to replace the poppet since they are inexpensive. One thing I wanted to check was if there was any corrosion in the tube but it looked bright and shiny. Squirrel season will be going out for 2 weeks soon so I will try to have the parts by then and pull it apart and go over everything. Thanks again, Gary