You definitely leave the co2 inlet valve open after you purge the atmosphere out of the pump body so you can maintain your set pressure. You can use any range of pressure in the pump body to control the performance on the pump.
The hole you are showing shouldnt have any effect on your pumps performance, but if its leaking from that hole then your drive shaft seal is bad, see this video at 2:40 for a better explanation of what i mean.
I would start by charging the pump with co2 and finding the leak with some soapy water.
My 150 out of the box leaked there also, ended up being a drive shaft seal and there is also a thin white platic seal between the pump and motor that was bad. ive been sent two sets of seals and pump still leaks. no help or warranty from MVP. pump is just an expensive paper weight now that has never been used. the 2 mvp60’s i have have been working for over 3 years no issues
Also if its a slow leak you can absolutely still run as long as you keep your co2 tank filled, you could also run nitrogen instead of co2 as thats cheaper.
Just make sure you are NOT leaking process vapors past the diaphragms.
Just found out mvp is closed but a company named garco ( not sure if that’s correct spelling) still makes em and has tec support. Hope alls blessed fam
