Running a MSD, after idling in the channel for about 20 mins today detected a fouled plug when powering up, imeadiately cleaned up underpower.

After idling back, 20 mins, pulled plug and it was black and sooty,
should I lean out the idle jets by two sizes? or leave alone as the only time i may be running rich is at a idle? I may be needing this much fuel @ 3,000 where I am still running on the primary jets?

Also is it wrong to use diaelectirc lube on plug boots to stop them from sticlking to the porcelin of the plugs?

Only one plug fouled or all of them sooty?

What carb?
Idle mix screws for idle mix.
Primary jets for mix up to point where secondaries begin to open.
Secondary jets for mix at WOT.

If holley, then power valve number can be changed to lean out motor at low cruise. Broken power valve diaphragm will make motor run sloppy rich from idle to 2200rpm.

If Q-jet, same applies except instead of powervalve you have metering rods. Won't be anything wrong with them because your problem just started happening...

Hello Guys,
If your plug fouling just started, look first for ignition problems-cap, wires, plugs, etc. It could also be a dirty or blocked idle air bleed. If you aren't sure what this is, find someone who does and have them take a look. If you like, you can pm your phone number and I'll call you and we can talk directly-it could take a lot of time to go through this on the board.