RE: How well did your YS run after sending it in for service?
If your friend sends his engine to YS Parts and Service they will honor the warranty.
I know for a fact that all repairs are run before they leave the shop.
Does your freind have a good glow plug in it? You said it was an OS F...that doesn't mean it was a working plug. Just becasue it glows doesn't mean its working.
If there is aproblem mechanically with the engine YS Parts and Service will fix it under warranty.
Like I said there are lots of enviromental issue that go into an engine running properly. Obviously you guys know what you are doing and you don't need me to help with the problem. The purpose of this forum is to help guys with engine problems. This is not a complaint area.
If the problem continues then send it to Service under warranty. The service department is very good at what they do. perhaps there is a problem that was missed. I doubt it not froma stand point that they don't make mistakes....but from a stand point that it ran properly for 5 tanks.......now its not. Like I said before lots of environmental factors....I suspect a bad glow plug or dirt in the fuel system.
maybe its just a loose bolt and an air leak. This can happen in a few flights also.
Troy Newman
Team YS