YS engines are easy to run, there is no fuss. Here are some pointers:

Setting - follow the instructions on the LSN and HSN, don't touch the regulator if you can, base setting is flush with the housing, remember the LSN is an air bleed, open (counter clockwise) to lean
Tank - make sure its strong, esp the bung, that is the weak link, buy a quality one
Plumbing - double check that its correct and that there are NO leaks, its obvious when there is a leak. Always release the tank pressure before filling up if not the YS will p33 on yer
Muffler - remove the muffler halves, clean with alcohol and tighten the screws using Locktite.
Fuel - 25% heli from Cool Power is heavenly
Maintenance - check the tappet clearance now and then, if you remove anything else that has a gasket, replace the gasket, the most minute tear will cause leakage problems.

Most important of all that you need to do is to show us a pic of the huge smile on your face when you first use your YS!