I've got a 21' Bayliner with a 9.9 2 stroke and it's more than enough to push my boat. I personally like the 2 stroke since it weighs about 45lbs less than the 4 stroke. That's just my opinion though. Make sure you get a different prop than the stock one though. Go to any dealer and they will set you up with the correct pitch for the size boat you are trolling.