Thanks Kerwin and Pit-viper
I will try both to richen and replace the fuel lines. Last time i ran the engine it was summer and over 90 degrees outside the other day it was 40 degrees when i flew it so i'm sure the mixture setting have something to do with it. It was fine during the summer i didnt have one problem with the Saito it ran great. Probably not a bad idea on that check valve at least the tank would stay pressurized with something like that. But changing the fuel lines and richening it a little may do the trick, i will give it a shot and see what happens.

thanks again
Link