Just trying to rule out...while waiting.
Also, what year motor and 2 or 4 stroke?
I am assuming by you are saying that the starter won't engage because it looks like you have replaced
Just to clarify, won't crank (as in starter won't spin) or won't start (but the starter will spin)?
You have a problem today.-------Test run with a known to be good tank and hose.---As per post # 5
If you can do it this way, I would say at least 30 psi of pressure but I think you will find out as you test.
Pull a water circulating hose