Your boat has a much better chance of getting up on plane by a single Evinrude E-TEC G2 than with a 4-stroke due to its tremendous low-end and mid-range torque.
You may want to visit www.etecownersgroup.com as they have a large world wide membership and may have some who are familiar with your boat and its characteristics.
"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.
I'm no tecnical expert on the mater, just a new G2 owner. I repowered a 22 chris craft walk around cuddy originally 200hp yamaha salt water series 2stroke wot 42mph. The G2 (200HO) just blows it away. No smoke, hole shots incredible and top end 50mph. I run the boat out the inlet drag baits for four hours and back to the dock most days on 5gals of gas my oil consumption is around 60 to 1 I believe. Im at about 110 hrs. I had the screens/water pickups changed to the next larger size as it did over heat after about 50 hrs, fixed the problem.