Check for strong fuel delivery to injection pump.
Plugged fuel tank outlet, plugged filter fittings.
Study attached pages.
Note return line from injectors to tank. This is a good way to assess if adequate fuel is being supplied to injection pump.
Rarely necessary to mess with injection pump and an inexperienced mechanic can easily make things much worse.
Another caution, when I read the words "finally got it started," I feel the need to caution about using Quick Start or Ether on Kubota diesels. A very bad idea resulting in bent connecting rods causing lower compression, broken rings or piston lands.
Dave