I have a 1988 25Hp Evinrude Manual Start Tiller...<br />When running it in a water tank in NEUTRAL and reving the engine, is it normal for the engine to backfire or cough? Only happens at higher rpm.<br />I'm not reving really high as I know you should not do this with no load on the engine...<br />I haven't put it on the lake to really try it yet...I'm trying to make sure everything that I can check before I put it on the lake is operating well....<br />Thanks In Advance.