A forklift should be inspected properly and given a test run before buying it. This applies specifically to trucks being obtained on the World Wide Web. It is important to find possible problems with trucks purchased from companies on line.
Starting the engine from cold is a good idea. Note whether there is excessive smoke and the ease with which the engine turns over. This is particularly crucial with IC engine trucks.
Testing the performance of the truck in tough situations must be included in the test run. An operator who is qualified can drive the truck in forward and reverse, up the ramp.
You could check an IC engine truck yourself. On a clear part of floor, run the truck around for several minutes while a qualified operator tests the hydraulic functions. Afterward, look at the ground underneath for indications of fluid leakage. Even seemingly minor leaking can indicate serious problems which would be costly to fix later on.
The masts and chains must be inspected by a trained individual. Check with and without a load that the mast works smoothly. Watch for 'binding' or sticking of the mast. A warning indication is play in the mast channels or between the fork carriage and mast. One more is creeping down or creeping forward of the mast when loaded. These can be signs of issues with valve, seals or ram.
The mast may have been changed at some time if the truck is used. Make sure that the mast and any fitted attachments adhere to the rating plate on a truck. Check that the sideshift is not sticking when loaded.
When checking the forks, look closely at the heel thickness for wear or damage. The manufacturer of the truck specifies minimum thickness. A loose fit could mean the hanger points or carriage are worn. Watch for cracks on the arms at heels and mountings.