Just because an air compressor is rated at 150 lbs doesn't mean it will inflate a MH tire..at least not in a time period that one can devote to the task or hold the chuck onto the valve stem. You have to consider the CFM that the unit delivers at a given psi. The Harbor Freight one delivers 0.88 CFM. But it doesn't tell you at what psi it achieves that rate of CFM. Look at a larger AC air compressor. They will normally give you the CFM at 40 lbs and at 90 lbs. The 90 lb rating is usually about 1/2 of the 40 lb rating.
That all may seem a bit technical but really it isn't. Just compare CFM to lb on any air compressor you are interested in. .88 CFM is only good for bike tires and any other low volume items. Yes, it will air up a tire, but its not going to air up a MH tire.