Hello there, Any input on running Autolite 25 Plugs VS Autolite AR25? This is a 11:1 compression engine, and my 25s are fouled black. Any input is appreciated...
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The AR is the racing version with same heat range designation as the regular Autolite 25, but has a back-cut center electrode and a nickel plated body.
Your problem appears to be too rich a mixture and I’d recommend you look at tuning the carb first using a wide band O2 sensor.
Thank you Joules for your input, means a lot to me. I will look into the O2 sensor to start.. I'm installing the regular Autolite 25s to see if that helps..
Hi Jerry -
While using oxygen sensors is probably a good idea, I would suspect your system wasn’t tuned to that condition originally.
I’m not sure what kind of carburetor or fuel injection you’re running, but that looks a lot worse than just a bad tune.
You may want to check on the basics….
- Float levels too high?
- Fuel pouring in at Idle?
- Idle Screws set way too rich?
- Leaking Power Valve?
Are the plugs the same on both sides of the engine, and are they the same front to back?
Anyway, with your plugs like that, your O2 sensor is going to tell you that you’re running way to rich. You might be able to get a jump on the tuning by checking on some of the basics…
Do you know a buddy with the carburetor you could borrow?
Of course you would want to start with a set of fresh plugs.
I’m sure that there are a lot smarter tuners here than I am. Hopefully some of those will also give you tips.
Let us know what kind of carburetor or fuel injection system you are running.
Rocky
Not only are they fouled but they are wet. Do they smell of gas?
...In my view, that's a Lot of Carbon for Just running Rich. A Blown power valve? The engine wouldn't even start or run, Flooded.
Looks like 'Burning Oil'. And there are a Dozen ways Oil can get into the Cylinder! Is there 'Blue Smoke' in the Exhaust, Or Black??
Just for general info...#26 Autolites Run Hotter. Would NOT solve your problem, but may 'Blast' away some carbon and keep the plugs a little cleaner. But that would just be a 'Band-Aid'.
As asked previously...are All the Plugs Fouled like this? Just ONE plug fouled could be a 'Weak' Ignition, up to and including a Bad Plug!
ALL the Plugs Fouled?...could Still be a Weak or Failing COIL, and Everything In-Between, Weak Spark.
Good Luck searching this Out.
MJ