I agree with those who say stop running the engine at the dock for the reasons stated.
If you are going to run the engine then actually run it under load for at least 1/2 hr, better longer. and don't just putter around. Get it up to normal cruising speed/revs.
I winterize my boat and it does not get run from Nov untill end of March or APril.
THe engine starts almost immediately. My engine is now 50 yrs old and has about 7,000 hrs.