I have the 3/4 hp and get only about 10 lbs pressure. Using to pump creek water for irrigation

1. When off, does it hold prime?
2. Did it ever work better than that? If so, has anything happened/been changed that could have been part of the problem?
3. How old is the pump?
4. Assuming you have run one pipe down to creek with a footvalve on the end... correct?

There may be an airlock in the suction pipe, and the 10 psi comes from just circulation of the water around the pump cavity. Or, it can be end-of life, when the pump will churn inefficiently.