That gook looked like bits of soft plastic. Biological I presume. But the asphaltine coating cleaned up easily with Penray Total Diesel Fuel System Cleaner and a small bristle brush. Flushed it all with mineral spirits. I found the specific problem with starting. In this photo, see the partially pulled out shaft with a somewhat L shaped fitting. When the fuel control lever is moved to shutdown, that shaft is mechanically rotated clockwise (as viewed). This then physically forces the sleeve control shaft to move the sleeves down on the injectors, spilling the fuel, stopping the engine. It is a mechanical connection, and the sleeves must be moved, or something will bend or break. When the fuel control is moved out of the off position, the pin that rotated the above mentioned shaft moves away, allowing a "torsion spring" on the sleeve control shaft to move the sleeves up, and allow fuel to be injected. This spring is fairly weak. That shaft was so stiff from the gunk that although the mechanism could move it to spill fuel, the spring would not consistently move it back. I didn't tear it apart, merely cleaned it up, including the bore of the shaft, and reassembled, with new gaskets.
Starts easy, and restarts easy. Thanks to all of you for your input.
