Hello Gazimoto:
I did flush the fuel tank with brake cleaner and found that it was indeed contaminated with what looked like particles of blue dope that I had painted the fuselage with when the plane was built. I will also sneak a small filter onto the line to prevent more paint from entering the engine.
I am also going to mount and level engine mounting pads on the engine mount. I think that the engine should be mounted in a stress free environment.
Cheers,
leomat