Weak log splitter

[calamari]

I thought I'd posted a lengthy description of a problem I'm having with a friends homebuilt splitter but for some reason it isn't shown.
It has a 6.5 hp engine and a Duerr pump model # 717-0887A which is apparently discontinued. It doesn't seem to go into the high pressure 2nd stage when splitting. It can split straight grain oak 10" and under but barely dents big 20"+ rounds. I tried to adjust the pressure valve on the pump but the screw just turns in both directions w/o going in or out. I can't remove it or increase the pressure. There's no "gear shift" to a lower gear when the pump goes into the high pressure 2nd stage.
So my questions are:
1. how full do you fill the oil tank? I've rented and used friends splitters and have overfilled the tank so that it overflows when the oil gets hot. I'm using hydraulic jack oil and put 1/2 gallon in the tank but it's still 3" down from the filler neck.
2. I can't find any rebuild kits for this pump. So. does anyone know what its specifications are as I can't find them? I want to look for a replacement pump if it's truly in need of repair.
3. Is there anything I can do about the pressure regulator screw to get it to work? Is there an alternate way to adjust the pressure or remove the screw other than through to top hole?
Thanks

 

[JeffHK454]

I thought I'd posted a lengthy description of a problem I'm having with a friends homebuilt splitter but for some reason it isn't shown.
It has a 6.5 hp engine and a Duerr pump model # 717-0887A which is apparently discontinued. It doesn't seem to go into the high pressure 2nd stage when splitting. It can split straight grain oak 10" and under but barely dents big 20"+ rounds. I tried to adjust the pressure valve on the pump but the screw just turns in both directions w/o going in or out. I can't remove it or increase the pressure. There's no "gear shift" to a lower gear when the pump goes into the high pressure 2nd stage.
So my questions are:
1. how full do you fill the oil tank? I've rented and used friends splitters and have overfilled the tank so that it overflows when the oil gets hot. I'm using hydraulic jack oil and put 1/2 gallon in the tank but it's still 3" down from the filler neck.
2. I can't find any rebuild kits for this pump. So. does anyone know what its specifications are as I can't find them? I want to look for a replacement pump if it's truly in need of repair.
3. Is there anything I can do about the pressure regulator screw to get it to work? Is there an alternate way to adjust the pressure or remove the screw other than through to top hole?
Thanks

First thing is a gauge needs to plumbed in..it will tell the story on what’s happening.

 

[calamari]

Thank you. I was hoping for someone to say, "Oh yea! I had that happen and it's the Slauson screw that needs to be replaced," but then that's asking for a miracle.
I don't have a pressure gauge and won't buy one for somebody else's splitter who doesn't take care of his implements.
I have now found enough information to be convinced that it's a two stage pump that's messed up. How badly I don't know but I think the useless pressure adjustment screw is a big clue. I can't find any information or discussion about the system or how to deal with the screw that won't come out..