I posted earlier of my 23 briggs / mikuni fuel problem. I've diagnosed to the motor receiving too much fuel. After several hours, the plugs fail. They are wet when I check after changing and running a little bit.

Can someone give me a run-down of possible causes for this, so I can go through the motor?

I checked the valve clearances yesterday to ensure they were still tight and correct, and made a minor adjustment.

Also, I believe the throttle cable is correct, as it is closed fully within the carb when idling.

My fuel / air mix screw on the carb seems to need to be turned way out for the motor to idle correctly. I know the factory setting is like 1 1/2 turns, but, at that setting, my motor is revving really high. I need to back it out another couple full turns to get it to rev down. That seems weird...

Any suggestions?

Re jet to a smaller size?

It should idle fine at 1.5 to 1.75 turns out, set the idle there (engine warmed for 5 mins). If not, you have another problem and should check the idle jet and float. You tune the Mikuni carb from idle up to WOT.