My 2 year mower broke. This is the 3rd summer to use it and it did well for 5 minutes and there was a shudder in the deck. I immediately stopped the blades and checked the belt, blade switch connector and fuse. All was ok. Cleaned the contacts on the blade switch and plugged back in. Nothing. Only thing thing left to look at looks to be the contact for the electromagnetic coupling. Anyone know where that is? Any other suggestions? Thanks