My engine is the second generation of FP's, aluminium piston with nickel-on-brass sleeve.
I'm running 10% nitro, 10% Klotz sinthetic, 12% Klotz BENOL castor.
I have tried several tanks (with and with out uniflow system and with and without using muffler preassure) and the problem continues.
No foam through fuel lines.
Engine is not hot at all after landing, you could easily leave your hand on the cylinder head for as long as you want.