yesterday i also decided it was time to see if my 73ES would run. I bought it last month and have been tearing out the interior and poking holes here and there to see how extensive the bodywork was going to be. It had sat for a few years at the previous owners.
The fuel pump was trailing the ground and a pressure line was leaking. I had ordered a couple of fuel pump mounts and i was planning on replacing all the old fuel lines and filter.
The fuel was horrible. Black and stinky. I replaced all the hosing at the tank, pump, and a new filter.
It was time to fire her up. No start! No pump! 0 volts at the pump. Cleaned and re-fitted the main relay and pump relay and didn't it start right up. Ran remarkably smooth for such cruddy gas and was very strong. Within 2-3 minutes it was purring. I am amazed at how it ran after probably 3-4 years of sitting.
I have lots to do but it was very encouraging that it fired right up.
It held even at about 1300rpm so I need to play around and find out why so high.....but that is another post.

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73 ES, 91 240, 98 S90