I use my decompression levers on my Yanmar 3 GM here on Long Island sound when sailing
on cold days in November and December. My lead acid batteries last me 6 and sometimes 7 years so they are
a little tired the last year or two in the cold weather when not so much sunlight for the solar panel.
Years ago was invited aboard an old wooden (barque?) that was anchored between City Is. and Hart Is. in western Long Island sound,
the owner explained that she was only partially completed in Norway when WWII broke out and was completed after the war
fitted with a surplus U boat diesel which he proudly started for me using compressed air from a scuba tank. Huge diesel caught on immediately.
The wrapped a line around the flywheel tale I heard went something along the lines of a Frenchman approaching land at voyages end found himself with flat batteries so he headed off on a reach, wrapped many turns of a spare halyard around the flywheel and ran the tail out through the hatch to a block near the rail outside the cockpit and thence up to the boom, then he gybed.
Sounds doable to me in a 1/2 baked hideously unsafe way, might also be useful for removing your engine from it's mounts and the shaft without any of that fiddly "removing bolts" sort of stuff if the line failed to pay out as intended, and for removal of unwanted companionway parts in any case.