I inherited a BCS 205 tiller from my grandpa not long after I was married. I have used it to work a 125'x30' garden on a West Virginia ridge for about 10 years, my grandpa grew about the same size garden before I got it.

It runs fine, has good power, my problem is that if I hit a big clod of clay, or piece of old tomato stake the tiller stops but the motor keeps running. So obviously there is something acting as a clutch. It is getting weaker over the last few years, and is the point I need to fix it.

Any ideas what is slipping and its location?
A formal clutch between the motor and gear box?
Clutch built into the tiller shaft?

I am mechanically inclined, but would like to see diagrams, talk to people with experience, and know where I to get parts before I tear it down and learn things the hard way.

Any replies are greatly appreciated.