I have an old Johnson V4, 90 HP. The year is about 1975.
I don't know what its like in other countries, I'm in Australia....

I currently fill my tank with Leaded (or LRP-lead replacement) petrol plus
50:1 mix of 2 stoke oil.

It seems that the petrol stations are going to stop selling Leaded and LRP
petrol shortly (some already have) so I'm a little worried about how I'm
going to get petrol for my boat.
I've heard about additives that can be put in to Unleaded Petrol for cars,
but does the same apply for 2 stroke engines???
In another place where I raised these questions, some people were saying
that I can use Premium Unleaded and it has a higher Octane level....
But i'm still a bit unclear about this and I'm trying to get as many peoples
opinions as possible... maybe people who have already made the
conversion????
Other people have mentioned things like the engine would need to be
modified??

Any help greatly appreciated...
Thanks!