Us premium unleaded fuel and 50:1 mix oil and you will have no problems.
You want to use the premium fuel to prevent detonation which will blow a
hole in the top of the piston.

--
Tony
My boats and autos - http://t.thomas.home.mchsi.com



"Grumpy" wrote in message
u...
Hi All,

I have a Mercury 500 Blue Band, yes I know it is old,. but it runs very
well
and has never missed a beat.

I was originally told to use leaded fuel with 50:1 oil mix. The fuel in
Australia is now lead free. The next suggestion was that I use premium
unleaded and add a bit more oil.

Currently I use the lead replacement fuel with 50:1 mix.

Any ideas on that?

Thanks
Alan