Can anyone recomend some good info sites on YS troubleshooting, I have a .63 that ran perfectly out of the box, until the third gallon, it just suddenly quit inflight, and now it's been a real turd, very unpredictable cannot trust it, this last time out it would not even start, just kinda ran on the starter and was blowing fuel out carb and exhaust. any resource helps for troubleshooting would be appreciated..............

Go to their web site click on tech tips, click on YS Doctors home page. see if the info you need is there. Here is the link...
http://www.ysperformance.com/

hope this helps

new glow plug? thats what happened to my os 70 surpass on its 3rd gallon or so

Sounds like timing! Check your valves for clearance! Also you can call Central Hobbies and ask them. WWW.centralhobbies.com

good luck!

Valves,Plug, regulator any could be a problem. Centralhobbies is a good call just as DD said.

Before you do though pull the valve cover off.
Turn the motor over till the valve's don't move for 1/8-1/4 of the prop revolution.
Take a dollar bill or a feeler gauge .05MM and slide it under both valves.
Adjust them so they are snug but not overly tight on the feeler gauge.
replace the Plug with an Enya or OS F.
Adjust the Regulator so it's flush with the housing.
Put a 12 X 7 or 13 X 6 APC Prop on it and crank it up. Should fire.

Try the YS Doctor. Very helpful.

YS Doctor