My 94' 100 hp Merc 2+4 idles rough and vibrates quite a bit at slow to medium speed. I know that it is a 2+4 there is vibrations during acceleration but I feel it's more than that. I've tried a 21 ss prop and a 17" alum and they both are very touchy at diff speeds. The alum is brand new (from a 75hp) and the ss has a few minor dings. Considering these props I've described would they cause a significant amount of vibration considering their condition I described? And is this engine have a history of idling probs etc? Thanks!
