140 fast hitch weak hydraulics

[Saucymynx]

Hello, I am back for more help. I have a 1972 140 with a fast hitch. The lift has seemed OK, lifting a 2 bottom plow and 6 foot disc. Not at the same time of course . Today I had a 60 gallon sprayer on the carryall to do some tick suppression and could not lift the tank when full. Between the liquid and sprayer, along with The carryall, the total weight was about 700 pounds. Only when It got down to about half full could it lift it. Honestly, I have no idea what the lift capacity of the 140 is. Does this seem right? If not, any thoughts on what the issue might be? I have not yet cleaned the hydraulic filter but now have the gaskets and will do that in short order

Thanks for your help