Stabil doesnt usually cause the engine to run worse. It just
smells a bit odd. Are you able to cut the fuel off to the engine?
If so close the valve and run it till the carbs empty themselves of
fuel.
(near the end hold the choke, that will empty them out)

Fogging the engine is a good measure, cant hurt. Really its a good
thing for long term storage. A few months in a garage??? It could be
optional.

After that's done, change the oil, oil filter, fuel filter, you can
spray the engine
down with a corrosion preventer spray. See if your boat has a
water/fuel seperator.
Check that out too.

Dont forget to drain that block, frozen water is not your friend.
Using a marine type of antifreeze might be an idea since some
water will be left behind in the block.

Change the lower unit fluid with fresh stuff. Make sure the old
stuff didnt come out looking like thick coffee. It could mean water
mixing in a bit. No good there. In any case drain and replace.
There are a few more things to lube up on an I/O like the gimbal
bearing etc. It wouldnt be a bad idea to grease any fittings
and cables with marine grease.

Oh well, just some thoughts....

Tom