Aussie
If it is like my older model 13-32.
The tension adjustment for the chain is at the rear of the mower.
Need to loosen locknuts on each side on bearing retainer, then tighten (both side) nut on threaded rod at the rear of mower. Each side should be done equal amounts so axle is square etc etc, i left about 3 mm play in mine. Lube it up and good to go.
As for your other problems I have no idea, my model has no adjustment in the pedal attachment???I don't think. seems to be solid linkages right through.
Keep us posted i am intereted to hear the outcome..
My clutch pads look OK from the outside but ARE worn and i have a bit of travel between F + R. I do have to put more prssure on F than reverse but nothing inconsistant like yours???
Go the Greenfields