it is sealed leadacid 2.3Ah about 8x2x2inch 12v, battery pops out and is protected by a fuse marked 40auto ...Now I find the round connector on the radioshack RADIOCHARGER is too small to fit onto center pin,...my auto recharge battery has a slow charge feature for both 6 and 12 volt ....will that work? I would be protected by the fuse if i connected it on the upside of the fuse wouldn't I?

What is an "auto recharge battery"?

You have to be somewhat cautious of the "battery eliminator" type devices.
Many of them "leak" a lot of AC voltage along with the DC component. If you have a volt meter, test the device on the AC scale and see if you have noticeable AC.

"sorry" should read "MY AUTO BATTERYCHARGER etc". As it was an ordinary transformer that put out 300mA 12v from radioshack had a 4way fitting for the 12volt socket that fit exactly, of the round type. I woke up the next morning and had a full charge on the battery and started the mower right up....worked fine but the transformer was rather hot...guess it will go on me sooner /later. A tricklecharge feature on the car's battercharger puts out 2 amps so I would guess that might be pushing it. This is the walk-behind electric start mower from cubcadet btw.

Do not use the car battery charger. The battery in your mower is a sealed lead acid battery.(AKA Gel Cell) Even 2 amps will overcharge it and very likely could explode it. No kidding. The correct charger probably has an auto- shutoff feature. That's why it's 28 bucks. Worth it to not blow up the battery.

I wouldn't want to even try, my method worked well without frying the wiring inside the battery which is very expensive to replace...btw...with no automatic shutoff you should use a plug in timer from your christmas lights like i did, set for 4 hours so nothing gets too hot. That applies to your car battery as well if you don't plan to sit there for 4 hours.