Ok, yes the engine is broken in. its 10% nitro Lube fuel i'm using with a 11x6 rprop currently but it was an 11x7.

I have flown F3F gliders for many years but moved to spain where there is not enough wind or hills to warrant gliding, so i've moved over to glow planes....
I got 52 speed engine as I knew it would take me very little time to learn to land on the runway and control the engine etc as the actual "flying" is not an issue.

Yes I changed the fuel tubing to the clunk as well.. it is ALL new.

Yes it was vertical when it cut out. The guy there suggested it could be due to starvation of fuel.

There is no spunge padding for the tank, could this cause problems?

I am going to try taking the whole tank system from another plane and plumbing it into this engine so I can proove wether the problem is in the tank section or motor section........