A forklift should be checked properly and given a test run prior to purchasing it. This applies specifically to trucks being purchased online. It is vital to detect potential issues with trucks obtained from companies online.
Starting the engine from cold is a great idea. Note whether there is excessive smoke and the ease with which the engine turns over. This is specifically vital with trucks that have IC engines.
Testing the performance of the truck in challenging situations must be included in the test run. A trained operator could drive the truck in forward and reverse, up the ramp.
You could carry out your own inspection of an IC engine truck. On a clear area of floor, run the truck around for a few minutes while a qualified driver tests the hydraulic functions. Afterward, look at the ground underneath for signs of fluid leakage. Even seemingly insignificant leaking can lead to serious issues that would be pricey to fix later on.
The masts and chains should be checked by a skilled person. Check with and without a load that the mast operates smoothly. Watch for sticking or 'binding' of the mast. A warning sign is play in the mast channels or between the fork carriage and mast. Another is creeping down or creeping forward of the mast when loaded. These could be signs of issues with valve, seals or ram.
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. Check that the sideshift is not sticking when loaded.
Looking closely at the thickness of the heel for wear or damage must be included in the inspection. The manufacturer of the truck specifies minimum thickness. A loose fit might mean the hanger points or carriage are worn. Look for cracks on the arms at heels and mountings.