Check the movie something Automaton. One guy tries at the end and fails miserably.
Wasn't really the greatest movie either.
Several reasons a chainsaw is a bad bad fucking idea.
1. I think this should be the most obvious, but a chainsaw doesn't give you much distance from the zombie.
2. Its going to make a big mess, and probably spray you with infected blood.
3. Once your engaged in attacking one zombie, chances are your not going to be able to quickly attack another one.
4. Its a lot of weight to carry, that doesn't really buy much positive for itself. Im not a fan of melee weapons but a good crowbar would come in much more useful(breaking into abandoned buildings and homes).
5. If have to put gas in it, and thats fuel that could be used for a vehicle to transport your ass.
Jesus, that paints a horrific scene.
i think i'll stick to axes and crowbars against zombies, and axes, and powers saws for cutting stuff.