Prior to purchasing a forklift truck, you must make sure that it is properly checked and given a test run. This applies specifically to trucks being purchased online. It is really essential to detect potential issues with trucks bought from companies on-line.
Starting the engine from cold is a good idea. Note whether there is too much smoke and the ease with which the engine turns over. This is particularly essential with trucks which have IC engines.
Testing the performance of the truck in challenging situations must be included in the test run. An operator who is qualified can drive the truck in reverse and forward, up the ramp.
You could check an IC engine truck yourself. On a clear area of floor, run the truck around for several minutes while a skilled operator tests the hydraulic functions. After that, examine the ground underneath for signs of fluid leakage. Even seemingly insignificant leaking can indicate serious problems which will be very expensive to fix later on.
A skilled person should inspect the chains and masts. Check with and without a load that the mast operates well. Watch for sticking or 'binding' of the mast. A warning indication is play in the mast channels or between the fork carriage and mast. Another is creeping forward or creeping down of the mast when loaded. These can be signs of issues with seals, ram or valve.
The mast may have been changed at some time if the truck is not new. Make sure that the mast and any fitted attachments follow the rating plate on a truck. Make sure that the sideshift is not sticking when loaded.
When inspecting the forks, look closely at the heel thickness for wear or damage. The truck's manufacturer specifies minimum thickness. A loose fit can mean the hanger points or carriage are worn. Look for cracks on the arms at mountings and heels.