Thanks for the replies,
I'm still not convinced its just a tuning issue, I had 1 flight the other day and the engine was lean right from the start when no settings had been changed from the previous days flying. I'm heading back out to the field tomorrow and I think I'll start with the factory settings again (and a new glow plug), but this will be the fourth attemp at tuning from the factory settings by 2 experienced heli people with no luck. Beyond this I'll be looking for something physically wrong with the engine etc.

One thing that was bought to my attention is that Funtech is now making a a pipe for YS50 its model is A395 HN-50 Type TE-3D, the current pipe that i am running is the A170 HN-50 Type R-3D. Has anyone had any experience with this pipe / engine combination?

Flyslow