I've run all sorts of motors on the side my canoe. If your canoe is stable, then there's no real issues with small gas motors as far as stability.
It all depends on what kind of canoe your running, and how stable it is. I've never been in a sports pal before, so I can't comment on stability. With a 2hp, any canoe will move along nicely.
On a side note...I have seen an intoxicated guy run a 6hp motor on the side of a sports pal. The side mount transom he made wasn't much more then a 2x4, and some clamps. Plained out really well. Untill the transom snapped in half, and the motor took off flying. The drunk guy didn't let go of the motor though. Ended up landing in the canoe ahead of him, prop spinning at WOT, foam flying.. Crazy.. Good thing he was alone in the canoe..