a couple months ago i rolled my ski and it wouldn't start again. i cleaned out the intake because it had some water in it put in new plugs and charged the battery because it was pretty dead. now it died while i was out and the battery was dead so i put in new plugs and recharged it. now it will run rough if i give it half throttle. when it died it kept on cutting to half power then back to normal while i was giving full throttle then just completely died and wouldnt start. both times it would barely crank an d the battery was pretty dead. i don't know why the battery keeps dying an d now it still barely runs after i charged the battery. an y help would be great. thank you