My 44 horse Yanmar is surging. I just replaced one of the exhaust hoses. The hose is a 3 inch hose and the run has two turns. In each of the turns there is a slight restriction due to the turn. We also just returned from a trip from the Abacos in rough seas. I had to replace both fuel filters while under way. After returning to calm water and retuning to our home port. I never noticed this surging. My ? is: will the restriction cause surging or should I look in another direction.