I have a 2020 Stihl ms201tc which cuts out when tipped forwards and down. It starts up and idles fine. If I hold it up as if to cut a branch it's fine, but I tip it down it gets to about a 45 degree angle and cuts out.
I've had it looked at and they're at a loss. Carb has been overhauled ( disassembled, ultrasonic clean and overhaul kit fitted), fuel screen replaced, new impulse hose fitted, fuel tank vent replaced, crank seals inspected, m-tronic reset. Fresh fuel used.
I've since swapped a known good carb and same issue, so can rule out carb problem. As it's been sat on the bench for a few weeks now I noticed its pooling oil, so although crank seals were inspected maybe have since failed? - I don't know (tbh I don't even understand how that effects it)
If anyone has any ideas it would be appreciated??
Thanks