If stale gas is a concern, then all of the other steps in-between zero power and your full start are also screwed.

Air compressors have more valves and gaskets that are vulnerable to oxidation, especially in salty environments, so I'd have thought the upkeep between the two, the two stroke would be easier.

But it's an emergency system, not a general operation system. Thus it's not going to be exposed to the salty environment most of the time. You could certainly put the whole thing in an airtight box.

Look at how the military builds surface-based missiles these days: it's in a factory-sealed box. Molten salt batteries so they last for decades. (You don't see molten salt in most purposes because once it's been triggered it's lifespan is in minutes or even less. They're used in applications that only need to deliver power once.)

It’s quite funny to think about.

Having good, fresh fuel on an oil rig. They need an engine that can run on crude.

Diesel will run on mostly anything if it’s running… including methane in the air intake, so you need to think quickly when presented with a generator that keeps running after cutting the fuel

Oil leaking around a turbocharger rotor seal also makes for good diesel fuel, if you define "good" as an exciting uncontrolled disassembly of the engine.

Crude oil from various wells has properties varying from ‘thick, stinky, corrosive goo’ to ‘explosive, barely liquid, bubbly mess’. Also, rigs need to be careful about ignition sources, as methane leaks can be a common emergency condition for some wells/crude.

It’s not the type of thing that using directly is economically feasible, even for emergency situations.