Following your directions, K11 pin 30 measures 22.6v without a load. Pushing the start button has no effect, does not change the reading.
Was that with a jumper installed from K11 pin 30 to pin 87? Install a jumper there, turn on the ign switch and push the start button.
with the ign sw on and trans in neutral K26 should energize. With the oil pressure switch seeing less than 15PSI of oil pressure(engine not running) you should also get K11 to energize(and an oil idiot light in the annunciator panel). K11s energized contacts(30-87) close the contacts and complete a circuit between pin 30 and pin 87. That sends the voltage coming in on pin 30, out pin 87 to the start switches. When you push the start button the power from K11-87 should flow thru the start button down to the aux start relay on the frame by the power steering reservoir. That relay should go clunk when you push the button as the power flows thru its coil to ground.
with the ign on and K11 30-87 jumpered the aux start relay on the frame should go clunk when you push the start button. If it does not, you need to disconnect the two small terminals on the aux start relay and measure them. One should have a low resistance path to ground, the other should have 24V on it when you push the start button. The two terminals on the relay should have some resistance between them indicating the coil is intact. you can test that relay with power from the batteries, connect ground to one terminal and 24v to the other small terminal and it should go clunk/energize(will probably crank starter)…
