07-22-2016 05:08 - edited 07-22-2016 05:09
For best results use a marine battery to which you can add distilled water if needed. Either a marine starting battery or a marine deep cycle battery is OK as long as it has a minimum of 500 cold cranking amps(CCA). In cold weather 675 CCA is required. This does not take into account the electrical requirements of the accessories on the boat. Get the highest capacity battery that you can afford and fit. Do not confuse MCA ratings with CCA ratings.
AGM batteries are very expensive and require a specialized charging voltage and procedure. Because outboard motor charging sytems are not designed for them, AGM battery life is shorter in marine environment.
"There is never just one thing wrong with a boat";
-- Travis McGee, main character in a book series by John D. McDonald
The factory recommends that a properly trained technician service your Johnson or Evinrude outboard motor. Should you elect to perform repairs yourself, use caution, common sense, and observe safety procedures in the vicinity of flammable liquids, around moving parts, near high-temperature components, and working with electrical or ignition systems.
The information offered here is only general in nature and should not be construed as complete factory approved procedures, techniques, or specifications. Always use the proper service manual for your motor, up-to-date service literature, the correct tools, and have an understanding of how to proceed with troubleshooting and repair methods. If you are unsure or uncomfortable with a procedure, a situation, or a technique, enlist the services of a factory trained technician.