Moves but doesn't

[Ratmotorhead]

Hello men , I seem to have an issue with my Clark cy500 forklift. If it sits all nite and I start it up in the morning ,it starts fine,but when I put it in forward or reverse it won't move. But if I leave it in neutral and rev it up pretty hard ,I will let it come back down to idle,and it will operate fine all day long.If I shut it off,same deal rev it up ,back to idle ,moves fine. I have removed the inch pedal parts and pluged off that line to eliminate that problem. Could it be that I am losing prime at my suction tube in tranny or hyd tank.it is clean on the screen. Any thoughts?

 

[Delmer]

Did plugging the inching pedal fix the issue? Losing prime seems better than any guess I have.

 

[Ratmotorhead]

Same results. Once I rev it up hard, it works great,keebit running works fine,lift tilt forward reverse high low good.shut it off ,won't move when I start it again. Rev it hard, back to business