the war eagle hull was originally designed around a Yamaha outboard, from the get-go. Back then you had a choice between a 3 cylinder 25hp and a twin cylinder/twin carb 25. Both mount the same way and sit on the transom exactly the same so it was "pick one".
war eagle's hull design is a great (perfect??) combination for hunting AND fishing; it does both pretty good. Notice that I said it doesn't do both perfectly because if you want a duck boat, you're looking at a different hull, and if you are fishing only, you're looking at a wider and probably longer hull, glass is the way to go if one can justify it. But the war eagle is probably the best compromise between the two. It pairs wonderfully with yamaha outboards because it was designed with yamaha in mind. The little twin cylinder was about 115 lbs; the 3 cylinder was a little north of 130 lbs as I recall, but was manual start only which many didn't like and rightfully so. The new 4 stroke 25hp is, as said, a shade over 125lb so a little lighter than the old 3 cylinder, and uses way less than 1/2 of the fuel, doesn't fog the air with oil smoke on first start, starts instantly even if you pull the rope instead of pushing the button. Best of all it mounts exactly the same as the old 2 strokes did. Actually most of the lower unit is extremely similar to the old twin carb 2 stroke, same water pump impeller, same propshaft, etc etc. I think the housing is the same, just a slightly different color. It runs better than the old twin carb 2 stroke did too. More responsive down low, variable trolling speed from 700 rpm to 1150 rpm in 50 rpm increments, at the push of a button, and it happily idles down to 700 with no issue whatsoever.
That said my dad has a yamaha F20 on his boat and it runs just fine. There are things I absolutely love about it and things I don't love. The negative is the tiller is a little short and it's not angled toward the operator nearly as nicely as my F25 is, but it IS a little quieter running (just a little), and it may be ever so slightly smoother at low idle, and that's splitting hairs. But it's down the 5 hp and you notice it. It doesn't have the torque to get up on plane and top speed is down about 3-4 mph on average. BUT....if I am reading properly the old style F20 (carburetor) is gone and is now the exact same motor as the F25 EFI, but 5 less horsepower. So there might be something there to look at....dunno...I'm out of the outboard business, for now.