Make sure to grease the outdrive, oring and case where the outdrive enters with some kind of seal friendly drease (Associated Green Slime, Noleen SF-3 suspension grease etc.) use the Carolina's orings too, they help.
When you tighten the case screws gradually tighten them in an alternating cross pattern so that they are even. Should have no problems after that.
"I have no idea what you're talking about, so here's a bunny with a pancake on it's head."
In mind and body, we're all heading towards old age. It is slower to go by bike.