Iím totally unfamiliar with your engine
but I found a parts
manual. The rack pin is circled in red and you probably need to extract the injector pump to get an idea of how the governor interacts with it.
Iím interested to know the magnitude of the engine overspeed. A fully open rack usually leads to destruction of the engine but you were able to calmly remove the fuel
line and wait for it to starve/stop....... that might mean only a high idle event with the governor still controlling the injector pump.........Iíd start off by investigating the settings of the speed control lever before removing the pump BUT take off the air intake filter and be prepared to block the air supply because no response to the manual stop is a a bad omen.