I’m at a loss, can anyone help? I have a Husqvarna 455 Rancher that is dying after two or three minutes on medium to high throttle. I have done the following to it: New piston & cylinder New crankshaft seals New bearings New muffler New carb diaphragms New fuel lines New tank vent I also tried a brand new replacement carb. It was first run with a full tank of fuel at idle so the new piston wasn’t damaged. It will run all day on idle. It only dies after revving it for two or three minutes. Once it stops I found that if I open the fuel cap and then close it again it will run again for two or three minutes. Any advice will be much appreciated as this saw is driving me bonkers.