Got a 2.5 merc that usually runs like a top........but today she cranked right up but seemed sluggish...I kinda thought that maybe It was because of the weight I had in my jon.....I stopped and put the electric down and fished.....when I went back to crank her she wouldn't start. Then I realized why she wasn't running good...the vent on the gas tank wasn't open. Usually she wont even crank with it closed but will crank right away with it open....She wouldn't crank almost like she was flooded but I know I didn't flood her....pulled the spark plug and cleaned it and still no go......I wonder if that pressure maybe did something to the float in the carb??? even after several hours of no spark plug in when I put it back she wouldn't crank.......any thoughts??