A forklift should be inspected well and given a test run before purchasing it. This applies particularly to trucks being obtained on line. It is important to detect potential issues with trucks bought from businesses online.
Starting the engine from cold is a great idea. Note whether there is too much smoke and the ease with which the engine turns over. This is specifically essential with trucks which have IC engines.
The test run must include a check of the truck's performance in tough situations. A skilled driver can maneuver the truck in reverse and forward, up the ramp.
You could carry out your own inspection of an IC engine truck. On a clear part of floor, run the truck around for several minutes while a qualified operator tests the hydraulic functions. Then, look at the ground underneath for indications of fluid leakage. Even seemingly insignificant leaking could indicate serious problems which would be costly to fix later on.
A trained person must inspect the chains and masts. Check with and without a load that the mast works well. Watch for 'binding' or sticking of the mast. A warning sign is play in the mast channels or between the mast and fork carriage. Another is creeping forward or creeping down of the mast when loaded. These can be signs of problems with valve, seals or ram.
The mast might have been changed at some time if the truck is used. Make sure that the mast and any fitted attachments follow the rating plate on a truck. Make certain that the sideshift is not sticking when loaded.
When checking the forks, look closely at the heel thickness for damage or wear. The manufacturer of the truck specifies minimum thickness. A loose fit might mean the carriage or hanger points are worn. Look for cracks on the arms at heels and mountings.