# Spark Plug All Crudded Up



## OptsyEagle (Jul 17, 2007)

Hello. I have a 16.5Hp Craftsman (2004) riding mower with a Briggs motor 
Model: 1C707 0230E1 021017ZE. 

I took the spark plug out (Champ.RC12YC) and it was covered in black dry crud that would chip off when scraped. This crud was on the electrode and insulator and caked in between the insulator and surrounding electrode. I am wondering what it means. 

The spark plug I took out last year seemed quite good, tan color electrode and fairly white insulator. This year I did switch from conventional oil to Penzoil synthetic (both 10W30). I also noticed this year that it started burning oil (never did before), about 1 oz per hour. I also started putting about 1% of seafoam in the gas to keep the carb and hopefully the engine clean. It is also supposed to stazilize the fuel. 

Any idea what my problem might be? The mower seems to work fine. Compression test indicated 105psi. Occasionally, small puffs of smoke emit when I engage the blades. I am tempted to go back to conventional oil, but can't really believe that this is my entire problem.

Would burning oil crud up the spark plug? Any help would be greatly appreciated.


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## b_bodylover (May 3, 2004)

Would burning oil crud up the spark plug? Any help would be greatly appreciated.[/QUOTE said:


> Short answer, Yep.
> Some engines develop this problem after changing over to synthetic oil from conventional oil. Usually ones where the tolerences have gotten a wee bit looser.
> Try going back to the type of oil that you've been using and see if that clears up the problem.
> Good luck,
> Charlie


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