I must be the lucky guy to have 8 Rossi engines and no problem.
Got at leat 8 Rossi engines for boat, plane, car.
None of them failed before.
The only problem is that each engine last too long and I can't change to new engine.
Rossi engines are quite reliable, I am using R5~R8 plug, 15% (max) Nitro.
I also have compared JP racing REX, JP Novarossi, Rossi last longer then those "Top" engines, but with slightly less rev.

Jacky