Can a gear driven hydraulic pump (ie rgn pump) be mounted with the ports vertical as opposed to horizontal? I tried this and while there doesn't seem to be any issues with the hydraulic side of the system , the gas engine that drives the pump is no hard to start.
if all pressure has been released from hyd. valve should not be any difference
If the system uses a closed center piston pump, you may need to add a dump valve to get the engine warmed up.
Ports really should not matter when I had a honda with a two stage log spliter pump hooked on ours that little engine was a bugger to start because its pumping oil immediately thinning the oil in cool weather helped some but I would have to hook the couplers together to make a loop warm the engine shut it off and hook to the trailer It was a temporary setup if it had to run long I would put a tee and high pressure ball ball valve back to the tank to make a starting loop of no pressure with out having to push though the valve and all the hose
Sounds like you are creating pressure as you start it....make sure your valve is open center and in neutral...also make sure your return filter is clean if you have one
And make sure the power beyond plug is out if the valve has that option
Problem was one of the valves wasn't self centering thus creating resistance in the circuit
sure makes for a hard start