This is an older Yanmar I purchased that was not running. I added a fuel filter (the fuel tank was connected directly to the injector pump), replaced the started solenoid, rebuilt the starter, replaced the ignition switch, and rebuilt the injectors. Now the tractor does a good job of trying to start but doesn't start.
So what do I try next? I bled both injectors. They both seemed to be getting small amounts of fuel. The tractor seems to have good compression because whenever you release the compression release the starter slows quickly.
I am an old farm boy use to Massey Ferguson, Ford, and David Brown diesels. These always started as long as they had good injectors, clean fuel, and compression.