Ive been down with a 3 degree burn on my leg.My boats not been run in about 3 month's.How far would a Good run be. Gonna still be down from March thru May..Total 5 to 6 months.

As long as you've been using non ethanol fuel you should be fine. Imo

 

BUT, I'm an advocate of not letting any engine sit for months on end without running......15 minutes would be adequate " in water ".

When I had boats, I put them away from November until early May.  Here's a couple articles on storing:

https://www.bassresource.com/fishing/Winter_boat.html

https://www.bassresource.com/fishing/boat-winterization-quiz.html

https://www.bassresource.com/fishing/winterizing_boat.html

Also, good luck with the recovery of your 3rd degree burn.  Very painful stuff.  I've got a scar from one on my arm.

It ain't stored  

I still hope to go. We fish all Year.

I'd say 15-20 minutes should get it good and warmed up. Goodluck with the healing process.