Craftsman riding lawnmower blowing fuses.?

I think the fuse is just for the starter circuit so that's rules out spark, safety switches, etc. Check for a wire that the insulation has been rubbed off or nicked near the off/on switch on thru the frame to the starter solenoid. Pay special attention where the wires go thru holes in the frame or near metal edges. If you were very careful, you could wiggle wires with the engine running to try to locate the problem. I guess a bad on/off switch could short out also. Intermittent problems are very hard to find sometimes.

Are you sure you are using a fuse with the proper current rating?

If your mower doesn't have a voltage regulator, or if it has one and it's bad, that could cause this problem.

Also, don't discount the possibility that there's an intermittent short-circuit that blows the fuse while the mower is running or being used - vibration or other mechanical movement could cause a short that disappears when the mower is stopped.

Try buying a slow burn fuse. Sounds like you getting a surge in the charger. Or maybe just replace the fuse with a breaker at the same amps. Then if it blows you can just reset the breaker and start it up again.

Both ideas will just cover up the problem but it sounds like it doesn't happen to often?