Consider making ship repair an Interaction, either something the player chooses to lock himself into with an animation, or a simple interact button like we have in some of the quests.
The repair will not start until 2-3 seconds after pressing the repair button. This entirely eliminates the ability to feather* repair the engine
Even simpler, the extinguisher could be given a charge up of 2-3 seconds before working, this will need visual and audible feedback as to not be confusing.
(perhaps shaking and smacking the extinguisher because it's old and malfunctioning)
Why feathering is bad:
I think it's too cheesy of a tech and a massive advantage if someone is sweaty enough to use it. Newer players won't know about this and wonder why their shots never disable ships and ultimately will give up on ship combat
*It is currently possible to tap mouse 1 really quickly with an extinguisher to permanently spam small amounts of repairs, this causes the ship to never be fully disabled and flight and guns will still work