log splitter pump won't switch stage

[girod]

My log splitter has worked fine for many years (like ten) but last year it started refusing to go to the high pressure (2.9 gpm) stage when it hit a tough chunk of wood. This is a 11gpm two stage pump, from Northern, for what it is worth. When it fails to switch it tries to split the chunk at the high speed low pressure stage, which overloads the engine and the engine stalls or nearly stalls. Once the thing warms up it mostly will switch as needed, but not always. When it does switch to high pressure it seems to work as well as ever. Do I need a new pump? What part of the pump is causing this problem

 

[triptester]

You could lower the switch over pressure setting. On the inlet side of the pump there is a hex shaped cap, under the cap is a screw for adjusting the switch over pressure. Turning the screw counter clockwise will lower the switch pressure.

 

[smokey7]

+1