Hi Guys
Many thanks for your input. I have finally decided to fit two nuts, similar to what they have on four-stroke engines. I can see that drilling the crankshaft and fitting a pin is very positive, but I don't want to risk messing up the crankshaft. Loctite is good too, but since I am using a wooden prop. when I come to remove it the heat might wreck it.
Thanks again.
JR