One last update. Appears that new governor spring was not the fix-all I had hoped. Appears that the governor shaft extending from the crankcase is not turning or functioning correctly. Can get motor to start & can get it to rev by manually advancing the governor arm, but not via the throttle actuator.
Seems we did inherit an S.E.P. after all. I'm no expert, but I think that would be a bit more of a major job to correct this than my rudimentary mechanical skills would permit. That and the fact I have no manuals for this or even a similar engine. Pity, it sounded quite a nice engine when it was running.
Thanks to BigTed, NormK, and the others who have offered their assistance on this one. And I hope the pictures I have provided help others, as I had great trouble finding images of a Sanli OHV400 linkage setup.
