On Jul 7, 2:46*pm, "StrimmingStress" wrote:
I was given a Ryobi PLT2543Y petrol strimmer

Compression? Is the cylinder barrel loose on the crankcase? Ryobi
are a bit prone to this, as the "cast-in" shakeproof ridges on the
crankcase bolts aren't too effective. If there's oil leaking from the
joint, or if the cylinder feels loose, then it's going to be low on
compression.

The fix is easy, but you need a Torx #27 as well as a #25, which isn't
a common size in the simpler sets (easy to get from most toolshops
though). Takes a few minutes.

Pop the four Torx screws from the crankcase end cover plate. Remove
the fuel tank (no need to disconnect it) and be careful not to loose
the rubber mounting bushes. Now remove the cylinder bolts and replace
them with real shakeproof washers as well. Re-attach the tank and
cover plate. Torques aren't crucial.