With a pump you have a valve that keeps air from getting back in, so priming works. With just a hose, and 200 feet of it at that, you need to get gravity or air pressure or whatever the hell makes siphons work sufficient to get the flow going without air backing up into the hose to break the siphon. It’s so much easier with any kind of pump, or at least having that check valve in the line somewhere.
Good point.
Glad we’re getting this thought out and won’t have to improvise at the last minute.
Couldn’t you just lower a bucket on a rope (assuming you could find a hole big enough to admit a bucket)?
Gas tankers have a hose smaller than a fire hose.
It’s a very small bucket. 
Ah.
They were getting it out of another vehicle.
Siphoning out of vehicles was implied in Walking Dead as well, although not shown.