I took my boat to lake this weekend and never had trouble starting so I did not run at home before leaving. Got to lake and it did not start or would sputter and die and not resart. Gas smells like varnish and it has been in there since fathres day weekend. Do I need to drain and fill with freash gas, or is there an additive that I can pour in to get it to burn and do I need to rebuild holley carb while im at it?