new to boating, bought pontoon with 9.9 evinrude 2 stroke, just would like to download a service manual so i know a little about it, seem to be having charging problems, installed sonar and cd player and battery went dead over weekend, pull started it seems ok now, also when idling or even mid steady speed it isnt running evenly, it will pick up a little back n forth, is there a reccommended fuel additive maybe new plugs?