My spark plugs are fairly well covered in black powdery stuff.

 

I have heard this means I have the wrong plugs or the car is running rich. I have fiddled around with the mixture and the idle screws on the carburettor to try and get the correct mixture as the manual says but the black stuff still comes back after cleaning the plugs and I am quite sure I have the correct spark plugs in there, and the engine seems to be running aswell as it ever did.

 

I am stumped, anyone got any ideas?:-\ Do I have to take it to a mechanic to get it properly tuned on a dyno or something?

 

Maybe carburettor needs a tune up?

if you really wanna get technical you need a shop with a CO (carbon monoxide) meter to set your mixture. its the "proper" way to get it right.

 

might be bad ignition components, cap/rotor/coil/coil to dist cable...

but if the car runs fine, other than carbon on the plugs,

might just be the 8 kajillion miles on the motor.

burning a bit of oil.....

what are ya gonna do?

 

i used to like to run bosch platinum plugs on the saabs when they started passing oil up the rings and blackening the plugs, seems they run hotter

without passing that heat on to the pistons..

sure dont want to go too far up the heat range iirc two steps up is max

havent toyed with that on the subarus... i've just been running stock listed

ngk's.

Choke set correctly?