If you really want to contact Evinrude Engineering, try sending a letter to the Sturtevant, WI address saying ATTN: Evinrude Engineering Dept., Chief Engineer
With a bit of sluething and Googling, you could probably find the gentlemen's name even.
"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.
The deal with the bigger BRP v 6 engines is that after 275 hp the case bangs its self up. This why BRP cannot compete with the Mercury. This was shown to me by A person that worked for OMC as A racing tech consultant. This person showed me the differences between the OMC engine, & the Mercury engine. (btw he raced A Mercury 200 weekends while working at OMC)