Are you planning on using the battery as ballast along with a system of pulleys to pull the cord or something? I don't get how the battery will be used without a starter.

I'll take a stab at it. The recoil starter is used on small engines like on lawn mowers, and even those mostly have a compression release to make it easier, since engines have become larger and more powerful over the last thirty years. The starter cord is wrapped around a pulley with a ratchet that engages the flywheel. It has a clockwork return spring for for rewinding the cord. Most larger tractor or large tiller engines already have self-starters powered by batteries. I suppose it would be possible to remove the recoil starter, cut a hole in the shroud and use an electric drill motor or air wrench to start the engine using the flywheel nut.

First: DO NOT use an air wrench or electric drill motor to try to spin the engine!! The result will be: The flywheel nut can and will break off the top end of the crankshaft, which will lead to expensive parts and labor!
that said--way back in 1983 or so, i bought a Snapper Hi-vac riding mower, with a 12 h.p. engine on it. It had electric start, and also the rope starter in the housing! That rope starter must of been a figment in the designers mind, as i could never pull it fast enough to start the engine, even when it was hot!
That said---bite the bullet, go buy a new battery, start the engine, and go mow! I'd suggest using a hack saw to remove that hand starting assembly, because, unless you have the arms of a Go-rilla, you will never be able to start it with the rope!

I am totally lost here. Are you talking about converting a pull starter to electric start? The rope on a pull starter just rotates the engine to get it running.

Your dumb question is on the Tractor Forum, where you posted it.

The air wrench could damage the crank, but I admit, I've used my Milwaukee drill to crank a motor for spark many times. I wouldn't use it to try to start it though. When it kicks off, how do you plan to get the socket off the nut in time?

I found this on amazon dot com. There are similar ones on eBay as well. Have no idea if they work or not.

Here is a link that might be useful: Spin Starter

I have a kit to install an electric drill motor attachment to start your engine.
First, there is a cone-shaped thing that bolts on the flywheel under the nut. and there is a cone-shaped rubber thing that goes into the drill motor chuck.
you push the thing on the drill down into the cone-shaped thing/cup on the flywheel, squeeze the trigger, and the engine would spin to start it, if everything was in order. There was no hard connection with the flywheel nut, so nothing got enough torque put on it, so nothing broke.
I saw a mechanic try to start the boss's lawn tractor, using a 1/2 inch drive air powered torque wrench! First pull of the trigger and---SNAP) and crankshaft was ruined, because the end of it broke right off, and left no way to tighten it down for reassembly, or use!

I'm with you, Rusty. Never use the air powered impact guns.

I've never seen or heard about the tool you described.

cone drive sounds like what you see on a chuck setup for a mill/drill. taper chuck? with the internet, all things are able to be sold to suckers. sounds like a billy mays special. now, i had a cheap 1000w generator and the recoil start broke after 5 pulls so i took off the sheetmetal cover and put a square drive attachment on my electric drill and it started with ease.

I now see in another thread that jim also used his new JD push mower to mow/till his garden. Sounds like the type of guy that is always "experimenting" and in the end ruins a lot of good equipment.