1980 m813 starting issues

[serpico760]

Been trying to turn over this thing for a while with the nh250 somebody tell me it's it a bad starter seems like the solenoid is engaging but perhaps the motor isn't trying to turn.
.The oil has been drained and the injectors have been pulled we were suspecting hydrolock perhaps but I guess that doesn't seem to be the case

 

[Superthermal]

my 2Cents...
I think I can hear the starter engaging but I don't hear the starter actually sound like it goes under load. Maybe to diagnose it you could put an amp clamp on the main power cable going to the starter to see what kind of amps it is drawing to know if it is actually under load trying to start the motor. If you don't have an amp clamp you may be able to measure the voltage of the battery pack to see how much the voltage drops when the starter engages.
If the motor is locked up that would suck. Could be a few other things to try but that is the first thing I would look at.