If I set my factory to output power, it'll do so, but it won't consume any power internally. This makes it impossible to have a steam engine setup since the inserters themselves won't consume power to pull any fuel off the line. Attaching an external power source to the factory doesn't work either.

How the hell do you expect your inserters to be able to start the boilers if the steam engines aren't running yet? "Output mode" means output mode, meaning that power only goes out, not in, so the only place the inserters can get power from is from the steam engines (which aren't running yet).

You need to kickstart your power plant, by putting some coal into a boiler by hand, or by replacing one of your inserters with a burner inserter, or simply by setting the power to input mode for a second.

EDIT: Whoops it turns out I actually messed up in the code. My fault, your complaint is completely legitimate.

No problem, I see it got fixed in the update, so thanks for that :)