|
Plug
Condition |
Engine Condition |
Recommended
action |
|
Shiny
and in good form |
Rich |
Lean
out the mixture |
|
Slightly
dull, but in good form |
Perfect |
Leave
mixture alone |
|
Slightly
dull, in good form, with coil slightly pulled out |
Perfect; tuned pipe
working well |
Leave
mixture alone |
|
Dull |
At the end of the
performance envelope |
Don't
lean the mixture, richen it 1/16 turn |
|
Dull
and mangled |
Operating under stress |
Richen
mixture |
|
Mangled
but shiny |
Head clearance too
close, or water |
If
no water is in fuel, raise head clearance by 0.0003 inch at a
time until plug condition improves |