Switch works, it's just rusty looking. I'm doing a restoration on a GF1800, so everything needs to look like new. Electrical is no problem, retired after 30+ years of large aircraft electric and radio systems.
You are spot on so adapting a switch shouldn't be a problem with your experience. Unless it must appear and function same as original you can use a secound momentary switch for glow plugs or starter if you are not succesful finding a switch with all positions. That is to say a conventional off ,run start ignition switch can be used by connecting start position to glow plug relay and use a separate pushbutton for starter or vs vs. A possible fly in the ointment is electric fuel shutoff but that is simple to convert to manual like used for decades on diesel tractors. Actually one could use a common ignition switch connecting accessory position to glow plug circuit. To start tractor turn switch to acc for predetermined period, then switch is turned to starter position until engine starts,when key is released it returns to run position. On most diesel pickups turning key to run starts timed glow plug relay then when light gos off key is moved to starter position. Salvaging glow plug relay from a pickup would alow use of a simple switch with .off ,run and spring loaded start but again the fuel shut off would be addressed separately.
The switch part number I posted does that.
