Hv 61 dying on side

[Stihl-in-Ky]

I have a 61 Husky that dies after a few seconds after turning it on its side to cut a tree down. It starts to lose power and act like it is running out of fuel will then die it also dies if you stand it up when this starts. It is then hard to restart. Any ideas would greatly appereciated.
Kerry

 

[RedFir Down]

Sounds like an air leak to me.
Do a pressure/vacuum test first.
That saw is getting long in the tooth, crank seal might be giving out on you.