Spelling corrected .I would not even try an electric impact to start a motor. I can almost guarantee you will either strip the nut out that holds the flywheel on or break the flywheel. If needing to use some outside source of power to spin it over I would use an electric drill without the hammer drill option.
@Red97 uses a setup that allows the saw to spin up without grabbing the impact/ drill and ripping it out of your hand . Basically it will only spin the nut/saw one direction, then free spins the other direction.