Yamaha safety mode?

I’ve posted couple weeks ago about having problems with my motor. It is 2004 Yamaha 115hp 4stroke. The motor was loud and could not get over 4000 RPMs on full throttle. I took it in last week to my dealer and they said they fixed it by changing spark plugs, tune-up, and making some adjustments. I took the boat out yestarday and it is the same. Loud and not getting past 4000. I called my dealer and they said it is possible that the motor is running in a ‘safety mode’ but they don’t have the equipment to check it.
My question is, does anyone know anything about the Yamaha safety mode, does this sound like what my problem is, and how do you fix it? Any other suggestions or ideas would be appreciated.

I think they are giving you a line. If the engine was going in to safe mode also referd to Limp Mode the engine would or should only go around 1500 rpm max and also it would be hitting a rev limiter and you would here a mis and possable a back fire or two