I am pressure testing my drive and am confused by how long the drive should hold its pressure. Some people say 15 psi for 2-3 minutes. Other people say 10 psi for 12 hours. In my case I pumped it up to 12 psi and it held for 1 hour. I left it for 12 hours and it dropped from 12 to 10. Since there is nothing that I can find in the merc manuals, does anyone have a clear understanding of the pressure and length of time it needs to hold the pressure?