Hope someone can help me out here... I'm helping a buddy with a 99 MULE 2520. it starts fine and runs good cold for about 3-4 minutes, then it loses all power under a load and miss fires ( skips). Pulled the plugs and the front one was very clean, the rear plug was black with carbon. The owner said the carb is new.. coil packs have never been replaced and the valves never adjusted.

Any point on where to start?

Thanks again.

Vic