Re: Merc service bulletin on prop exhaust hole drilling
Mark, there are a number of vented props that have the holes already drilled. There are also a good number of them that have plugs to fill the holes as needed (adjustable). The requirement for venting has as much to do with engine height, hull type (hooked, no hook, rounded, pad, etc.) and prop style. I don't rmember the service bulletin you're referring to but there has been a number of articles on the subject. The problem is that you can take a perfectly good prop and screw it up in just a few seconds. Your best bet is to buy a prop that is already vented by the manufacturer. They've tested several configurations and the props are vented to accomdate most of the variables I've mentioned.
That said, if you have a spare prop that you want try venting, take a look at similar style props that are already vented and that will give you an idea of how you should vent yours. The process is nothing more than drilling holes but getting them exactly where they do the most good is the trick.
