I'm going to look at an SD that supposedly ran ran, then wouldn't start. I feel ready for the usual stuff, filters, priming, glow plugs, but where's the glow plug strip fuse?

Follow the glow plug wires to the relay.

Check for the old screw-down-handle type primer pump. Several cars have changed hands because the primer pump started leaking, causing the engine to stall.

__________________
Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

Do you think you could duct tape it (or some kind of self amalgamating tape) long enough to get a couple of hundred miles, then change it at home?

Don't know about that. For the $12 or so that they cost, I would just buy one ahead of time. If it turns out that you don't need it, then keep it as a spare. However, if you perform the fix in front of the current owner, you run the risk of the price going north or the deal going south.

__________________
Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References