Here's another spark plug related question...

[bob888]

I notice a patch of black discoloration on the inside of the upper cowl, just above each spark plug. I suspect this is electrostatic carbon deposit. Does this mean I need new spark plug wires (I inherited the ones on there with a used engine and they look a little frayed just above the spark plug connector)?

 

[rvsxer]

Slick claims a service life of 10 years or 1000 hours for their ignition harnesses. If it's been in service much more than that I would change it. I just changed mine after 17 years and 1400 hours and fixed a rough-running issue. That harness looked and tested good.