RE: Prop Nut: Is there such thing as TOO tight?
Four strokes are usually double nutted but if you are too lean like Mike mentioned they can still toss the prop when they back fire. I haVE USED SINGLE PROP NUTS WITHOUT PROBLEMS BUT WITH ENGINES THAT HAVE BEEN RUN AND IN TUNE. Over tighten?? I think the threads would strip on the nut before I got it over tight. I have often used the nuts with the washer behind them. I ran out and took a photo of an OS 1.20FS I'm putting through testing before I put on a spinner. This one is double nutted. There is the washer, standard FS nut then the spinner nut. I use a piece of piano wire about five inches long to tighten them, it's a little bent but you know if it starts bending you have tightened it good enough. If the engine is rich enough it woun't back fire and toss the nuts and prop, start fat and work into the lean.