Combines 1688 hydraulics

The hydraulics were improved a lot between the 1688 and the 2188 and the problems you mention go away. I would guess they either switched pump styles, pump sizes, pump pressures, or maybe all three. I doubt there is much hope for a retrofit solution. We have the same issues with our 1680.

They went from a gear style pump- to the pfc pump which can produce full flow or close to at significantly lower rpms compared to a fixed displacement pump like on the 1600 sries

1688 and 2100 have basically same hyd except the valve. first issue is probably the accumulotor valve is partially open. close and you should have instant up and down. if it raises faster as you speed up rpm it probably needs pump. but is normal for low flow at low idle. also make sure your unloder switch shuts off in out position. will heat oil and ruin fflow.