The E-TEC 115 HP outboard was introduced in the latter part of 2006 and is essentially the same design for the past 13 years. Your motor is definitely not a test or "debugging" motor.
It is important that the motor be propped correctly as the engine has to run at full throttle close to the 6000 rpm limit. There is an exhaust tuning movable valve in the midsection that has to be exercised to keep it from freezing up or being carboned up. Because the motor is run mostly at slow speeds, it does need an occasion blast of full throttle to keep it operational.
Your dealer should check the actuator, linkage, and freedom of movement to be sure everything is operating as designed. With a laptop and voltmeter the tech can also check starting voltages in the system and at the starter to be certain that electrically things are in spec.
Evinrude has a dealer support team if your tech needs assistance with troubleshooting any problems.
"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.