Honda HRX217TDA only going one speed

Hi everyone,

I have a Honda HRX217TDA lawn mower that's only going one speed. It has the three speed setting on the adjustment handle. It does move but it seems like it's too slow, possibly stuck on speed one. The cable moves freely and I've attempted to adjust it by moving the adjustment bolts up and down but I don't think it's made much of a difference. The owners manual only lists this fine bolt adjustment but nothing else really regarding the transmission.

Any suggestions where to go...

Honda HRX217TDA only going one speed