One more thing...
I would suggest that you also spend the additional couple hundred bucks for a good outboard bracket that will support the 10 hp four stroke. I did, in anticipation of my eventual upgrade to a four stroke.
It gets the outboard up out of the water better, but the thing I like the best is the ability to rotate the outboard fully. I found with the outboard mounted in the factory transom cutout that I could only turn it one way. With the tiller on the outboard tipped down so it was usable, it banged up against the edge of the cutout when you tried to turn it to port (turn boat to starboard).
When just motoring down the river here, it doesn't matter, you still steer with the boats rudder only. But, when you are docking the ability to turn the boat in it's own length with the outboard is very handy. Moving the outboard back by mounting it on the bracket allows you to do this. The downside is it pushes that extra weight further astern as well. I have found the tradeoff to be worth it. Maybe it has to to with our conditions here that has wind, lots of current, and finger slips.
A few weeks ago I ran aground. With the outboard mounted this way I just turned it sideways, and the boat pivoted on it's keel until it was facing the exact opposite direction. It still wouldn't come off (!^%$*&^$), but it did not take much else to get cooking.