Have a Theoben Fenman Gas Ram in 0.22. . Circa 1998 according to the serial number. Never been serviced as far as I am aware.
Over the chrono it is running at 9.5ft lbs.

I have found it prefers RWS Superdomes 15.9 grains. 5.52mm head to JSB 15.9 grain with 5.50 head.
Should I be trying a lighter pellet such as H&N at 14.6 grains but head size is 5.53.

At 15 yards (back garden) bench rested decent sub 1" groups.

My Questions to the forum
Should I have it serviced or should I simply adopt the stance of "if it ain't broke don't try to fix it".
Is 9.5 ft lbs acceptable & if serviced & increased to say 11 ft lbs will it be more accurate or simply more "twangy"

Thanks
Al