Just ran a vacuum test on 2 separate pumps no vacuum pull at all. Eccentric must not be engaging the pump arm. Does anyone have the specs on the eccentric? are there different models?
Please take the pump(s) back wherever you bought them, tell them they're defective, and get your money back.
Remember, "the customer is always right" the parts store won't question your diagnosis.
The specs on the eccentrics are all the same, HD models are just made from beefier materials and coatings.
Don't waste any more time on this! Some of us have been right where you are now.