Last November I began winterizing my C270 and then got tied up at work and asked my boat yard to winterize the boat when they hauled it. When I got the bill I saw that they added diesel fuel stabilizer. Problem is, I had already done so. Now, if they added the correct amount, I have twice as much as I should. Will this be harmful to my engine? Do I need to have all this fuel drained or can it be used? Is there a counter treatment option? My engine is a Westerbeke 20B Two. Thanks for any assistance