I have a 2005 Husqvarna,model 2654, riding lawn tractor. My problem is the engine is losing spark to one cylinder frequently; so much that I can't finish cutting my grass. When you first start it, it will run fine. After briefly using it , it looses a cylinder. If you stop and go back to it, sometimes it will work and sometimes not. Any ideas??

You probably have two coils, some models had one coil, but more often you see the two individual coils. I would think that the cylinder you are losing fire on has a coil that is going bad. You see as the coil "works" and gets hot, it separates, causing the coil to stop firing.

It could also be a bad spark plug. A weak spark plug will also quit working after it warms up.