1. valves dont use pressure to control work,they just direct flow..the flow pressure backs up and increases thru the valve due to load being moved, ie:-cylinder extending to lift a load or a motor moving trying to rotate,propel or move something.Your pressures at rest (not moving) should be minimal,if you are seeing pressures and the motor lugging down at rest then you definitely have a problem in valving or plumbing. The only thing a valve uses pressure for is to actuate the relief valve (in it if equipped)-to open it for a high-pressure relief bypass back to the tank. Flow should be straight thru from the pump or flow divider thru the valve back to the tank unless a spool is moved(handle pulled) if you have pressure with all handles in neutral then you have excess flow restriction or a plumbing error. Fitting sizes can effect flow as well,too small a fitting or elbow can also restrict flow. Small flow into a big fitting is OK but not the other way around..this backs up flow making pressure and heat which is what you are seeing.
#2 in a circuit with a power beyond valve,the PB valve should be the first valve in the circuit, a secondary flow will use the power beyond port off that PB valve to feed the second valves' flow input. When you actuate the power beyond valve, the second circuit has it's flow interuppted and the first circuit (w/power beyond valve) gets the flow. When you let off the first in line power beyond valve and it pops back to neutral position, the flow to the second valve resumes. My power beyond valve runs my articulated steer function,the power beyond flow goes to my loader valve. When I steer, my loader functions pause (except bucket down) until my steer valve is neutralled again. The power beyond valve does not regulate flow, it just steers it from one valve downstream from it or not..the priority flow is the one plumbed to the P.B.valve itself. Either a valve is power beyond or not..there is nothing you can add to a non-power beyond valve unless it has the capability from the factory with a PB plug port built in like the one in my photo.The photo of your yellow valve looks like a standard two-spool valve with a relief valve(silver long hex barrel above the inlet port) on the input side..what is going on with the tee and smaller hose on the input port is beyond me.
#3 the 20hp Kohler isnt any different than the 18hp Briggs when it comes to turning a pump, as long as the rotation is correct..most small gas engines turn the same,CCW which means you need a CW pump if direct coupled. I think you have some valve adaptations that werent carried out correctly..you need to troubleshoot the hydraulic schematic front to back to see if there are changes to it.again my guess from here is you have some valving mods that were plumbed or valves routed incorrectly.
#4 some parts are starting to trickle in,only via FedEx or UPS..USPS is all mucked up right now,total BS,they have bad apples in the District Heights Wash.DC sorting center..and some vendors dont ask your preferred shipment method..USPS was stellar in delivering small parcels in the past but since the changes everything is screwed up. I'm almost 30days stuck in USPS on some parts..the ridiculousness continues.Even with Informed Delivery and starting a inquest w/USPS the issues persist..They blame it on Covid and package volume..not the case at all.
