Dwarven Machinist fuel?

Do machines built by the Machinist need fuel? Automatons from what I gathered from fiction usually have some gear related design that doesn't seem to need fuel. I can dig that for the most part, how else do adventures go into a machinists tomb and fight his robots 200 years after he has died. Also it’s a game with magic I can stretch my belief.

But what about players that want to make flamethrowers and  jet packs? Are you to assume that all flying is done with giant machine wings or an aerial screw esk thing? What if my player wants to make the iron man armor?

And if they don't need fuel what if they want to use fuel as a restriction? Would it be too good to give that a negative -2 abilities for the machine? Maybe -1?

 

Edit: In my quest I have another question: Mechanical Engineering is in the custom power list not the Proficiency list. Also as mechanical and magical engineering is very similar, and so is machine building and making magical items, I have to ask why the Machinist doesn't get his Int bonus to the Design/Build/Repair checks. 

Does Repairing for an hour heal all damage? Does it cost anything?

Edit:Edit: I've seen it mentioned in the posts but I can't find an asnwer in the book. Does having blueprints cut costs and time for building like magical items? 

In my opinion, fuel or ammunition are not restrictions for dwarven machinist constructs, any more than they are for magical constructs. This is why I joke about ancient egyptian laser beams (well, that, and because they’re awesome). If fuel or ammunition were needed as a restriction, it would be mentioned; no mention means no restruction.

How many additional powers it was worth would depend on how often it needs to be refueled and how difficult it is to refuel (both in terms of getting the fuel and in terms of putting it in the machine).

When repairing, the machinist repairs his class level worth of damage with a successful proficiency throw, the attempt requiring one hour. (Player’s Companion page 20.) No cost is listed, so it doesn’t cost anything other than the time.

(Note that I am not an Autarch and there is always the possibility of me being wrong.)

I figure perpetual motion machines are probably less incompatible with thermodynamics than fireball.

Do machines built by the Machinist need fuel?

No. However, if you wanted them to require fuel you might allow that as a restriction. The number of negative abilities would depend on the frequency and cost of refueling. Sadly I don't have a spreadsheet with this answer already written, so use your judgment and let us know how it works in play!

In my quest I have another question: Mechanical Engineering is in the custom power list not the Proficiency list.

It's errata. It's been updated in the latest version of the rules.

Also as mechanical and magical engineering is very similar, and so is machine building and making magical items, I have to ask why the Machinist doesn't get his Int bonus to the Design/Build/Repair checks. 

Sadly I don't remember if that was intentional or an oversight and my notes don't make it clear, either. Dwarven Machinists are not over-powered so I think you could allow the INT bonus without issue.

I've seen it mentioned in the posts but I can't find an asnwer in the book. Does having blueprints cut costs and time for building like magical items

No, they do not. When building magical items, having a formula is considered advantageous relative to having just the spell required for the item. When building automatons, there is no "spell" so the blueprint is the prerequisite.