In 2010 they came out with a gear reduction starter to replace the direct drive version that your motor has. If your problem is the starter, replace it with the newer style for best results. You will have to trim away a small area of the flywheel shield to accommodate the new starter.
First use a voltmeter on the starter post and starter frame and monitor the voltage as the starter cranks the motor or tries to. If it is below 10 volts, the battery, connections, or cables will need to be repaired or replaced.
"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.