Can be done.
But why? A 15 HP motor is plentiful. Pick your poison....Yamaha, Tohatsu, Merc, Mariner, Johnson, Evinrude, Nissan, Honda, etc.
If you're stuck on the 1448 with the 20" transom, you'll need a long shaft motor. Trade. Or sell your shorty and pick up a used long shaft. The 1448 will like a 25 though. The 15 is a little on the smallish side.
It's easy to use a jackplate on a 16" transom for use with a 20" motor, but very challenging to use a 20" transom with a 15" motor.
Went through it a while back. Bought a boat with a 25 Yamaha 4 stroke 15" shaft. Sold the boat, ordered a new one with a 16" transom. Found out that particular boat was not available with a 16" transom, had to get a 20". Sold the motor for $2200 and bought another used long shaft 25 (same exact motor but long shaft) for $800, fixed the foot for $90 and I still use it. Every weekend when the weather will let me. Play the cards right and it's possible to come out smelling like a rose
....and now, a year later, I'm finding out that Yamaha is "supposedly" in the testing stages of a new "SHO" 4 stroke 25 Hp. Lighter, faster, etc. Whether or not it actually carries the SHO name or not is to be seen; and whether it actually makes it to production is to be seen. I want one if it does...especially if it is what I think it's going to be. I'm thinking under 140 lbs, 3 cylinder, EFI. The market for the current F25 is dead. ~180 lbs is what the current F25LEHA weighs in at! Without tilt assist, you CANNOT tilt it from inside the boat. Well maybe Chuck Norris can, but I can't.