Just thought i would give an update on how the 175 is going.

Excellent after sales service from the Australian YS distributor Tates Toy World. Thanks Eddie.

The back plate, ignition module and the fuel regulator was changed during the fault finding process from my 170, which resulted in the engine running perfectly.
The back plate and ignition module were replaced under warranty and fitted to the 175 to confirm all is good. I also refitted the original regulator.
I have since had 15 flights and the engine is still running perfectly, with no misfires whatsoever.
Just what i expect from YS.