Help Please
 

Hi guys,

I have an old Mercury 500 Blue band motor 50HP, The motor has been running
ok without any probs for a while but today after about 45 mins relaxing on
the water, It would not start. eventually I managed to get it going and
limped back to the marnina idleing all over the place.

Now a bit of background. When I got the motor I was told to use leaded fuel
with a 50:1 oil mix. When the leaded was removed from the market here, I was
told to use Premium unleaded.

When I removed the plug whenb I got back, they were black and wet. I cleaned
them off, and the motor took first time and idled like a charm.

Cud it be the carbs are running rich, is the oil mix wrong , any help
please...

Thanks
Alan