Man, glad I actually went into the D.I.Y. section...

I have the SAME EXACT problem... Just ask ROF... My crapsman riding lawnmower is lucky to keep the same battery in it for the whole summer.... Now I will be unplugging the neg cable....

Turn everything off and remove the positive battery cable. Be sure battery is hot. Barely touch it to the post and if you see some little sparks you know you have something pulling juice. Find it and fix it.

That's EXACTLY what it's doing. Wonder if it's the lights? I unplugged the wire to them

key switch or starter circuit has a short in it is my guess, just rig a switch from the neg cable so you can shut it off after use if you can not find the problem.
make sure its a 30 amp switch or higher and use the same guage of wire as is on the battery.

Wonder if I can put a push button start, and racing slicks on the back? Maybe bore the engine out and add some more HP?

just adjust the restrictor setting a little bit to get more power.

if you can't I know a couple of good ole boys here that can, they have one that will do 85+ with 425# on it. they have about a dozen they race.

I had a Husky ridin mower that started corrodin bad on the cables first then on other parts of the engine.had a heck of a time tryin ta figger out why because it was kept in dry shed.Then someone asked me if by chance I had a opened bag of fertlizer in thar and yes I did.Not only was it causin the mower to corrode but anything metal in the shed.Had to git new shovel,rake,hoe,etc:.Even the inside of the metal shed was eatin away. Wont be doin that no mo.

alright I am no mechanic but shadetree beerholder I am, I do not know all the proper terminology, so stick with me.
I have had same problem. I took the top cover off the moter, follow the sparkplug wire back to the *^(&9 ? this is what charges the battery, if you take it off it is held by two bolts. clean it up with wd40 and light sandpaper.you will also see the magnets on the inside of the wheel. clean these as well. when you put it back together be sure to use a thick peice of paper for a spacer in between. charge battery and let it run. this should solve problem or at least give you something else to try.