Check hydraulic oil on sight level gauge on hydraulic tank, pumps would be making noise if oil level is low. Make sure all hoses are connected properly and not damaged. Check couplings and make sure they are plugged in properly.
[pdf] It should turn around smoothly, without any 'hickups' (be sure to completely shut down the air compressor!). Check the isolation of the motor windings. Should be in the mage-ohms (you need an isolation tester / high voltage ohm meter for this). Check the voltage when the compressor is running.
[pdf] But here is the silver lining: cheap, affordable geotechnical drilling rigs are plentiful and price with performance. In this buyer's guide, you will learn important considerations in choosing the best geotechnical rigs for small contractors and cost-effective soil testing strategies.
[pdf] 
