you don't say if this is LPG or gasoline, if Gas, check the fuel filter and fuel lines for cracking on the side before the pump (suction side for leaking air into the line when vibration gets strong, air being able to leak in, when no fuel leaks out.)
I would also consider the temp sender circuit. if the engine is getting too hot or thinks it is too hot, a speed/engine rpm de-rate then shut down would be expected and normal to protect the engine.