In reply to Beer Baron:
OK, I'm back.
Buying a used Forklift can just as hazardous to the untrained masses as buying a used car. There is no shortage of unscrupulous used machinery dealers willing to polish the stinkiest turds and sell them to suckers that don'teven know what they need, for top dollar. To many a repaint and new decals is a reconditioning job, they don't even bother to clean out the insides, for fear all the leaks will start showing themselves.
Knowing what you really need in a machine, what machines are capable of delivering that (in the real world), and a prepurchase inspection will go a long way to getting you a great deal and avoiding a rip off.
First you need to carefully analyze what you need the machine to do, where it will be doing it, how much weight it needs to handle & at what height, and what attachments, if any, it will need to handle.
All modern forklifts have their weight rating based on a 24" load center, that means the COG if the load should be no more than 24" from the face of the carriage (the part the forks attach to). Many machines are not rated to lift their nominally rated capacity all the way to the top of the mast's lift height. All machines should have a factory supplied capacity data tag explaining it's capacity vs lift height. Adding attachments or handling loads with greater that rated load center can drastically effect the machine's real capacity.
For example, if you've ever been to a carpet warehouse you've seen forklifts with a carpet ram attachment. Even though those big rolls of carpet usually weigh less than 3000# you never see a forklift rated less than 5000# handling them because the load center is nowhere near 24".
So if the metal vat of spent mash weighs 3000# but is more than 48" in diameter you will need a machine with greater than 3000# rating to safely handle it. You stated 2000# plus the vat, I'm assuming the size of the vat will put the load center past 24". IMO a 3500#/4000# machine would be a safer choice.
As far as damage from overloading is concerned, I've never seen a machine damaged from it in anyway except being flipped over (which, BTW, can happen in the blink of an eye). The mast and frame structures of machines in the 3000# to 5000# range are pretty similar. Lift chains are a wear item, and they will in time stretch to the wear limit wether lifting 10% or 110% of the rated capacity. The relief valves are set well below the burst pressure of the hoses, sometimes 50% below. Hoses fail from wear and tear, abuse and old age, not overloading.
I'll come back later with a post about Internal Combustion Engine (ICE) vs Electric