319D Slow cranking, no start due to engine load from hydraulics

[britten44]

My JD 319D will not crank fast enough to start (less than 180 RPM). I replaced the starter (burned out the old one), battery, and checked the wires for voltage at the starter. Everything seems fine. The manual says it could be from engine load due to hydraulics. Is there a solenoid or something that opens during cranking to reduce the drag on the engine? Is there an easy way to determine if this is the correct diagnosis such as remove the hydraulic filter and put a bucket underneath just to see if it starts? Any help appreciated.

 

[foton]

if there is no draw on the hydros the system should be bypassing, maybe what ever and where ever that valve is , it is stuck closed or activated ,check all your switches. I know nothing about that machine,I thought any responce would be better than none.