Theoban Fenman Strip Down/service

[Mat2803 18]

Hi iv not had anything to do with gas ram rifles in the past and iv just chronod my mates theoban and it's really low on power 5.67ftlb at 397 fps now iv been on Google for a bit of info and tried to find an exploded diagram with no luck I understand how they operate and do my own restorations and tuneing on spring rifles but not have any experience or diagrams I'm reluctant to strip it until I have a diagram

So I'm just woundering is this just a case of topping the strut up and trying again on the chrono to see if it drops power if so then doing a service iv read that people power these up and that in turn creates the crown/ piston seal to vaporize to the point of distruction inturn leading to damage inside the main air tube

Does anybody have experience with these rifles thanks

[andy97 209]

try with the pump first mate then go from there