My 371xp

[Timbercruiser]

Hi all i have a new to me 371xp I rebuilt the motor and carb with oem stuff. The saw is a great saw i like it but  i have a problem. When i tip the saw on its side to cut a tree i loose rpms I checked it with a tack and yes when you tip it over it loses about 400 rpm. I changed the fuel line the pulse line and tank filter with the same results. Hopefully someone has had this before and can help me.  Engine seal etc are new it runs great other than this fact I can use it still but noticed this happening. Hope you guys can help  :D

[HolmenTree]

Check your intake manifold for damage or poor seal.

[Yatt]

Did you do a vac test after doing the above work?