Small Engines (Lawn Mowers, etc.): Spark Plug Condition, cub cadet 1046, crankcase oil

Question
QUESTION: Hi Paul,
I have a Cub Cadet 1046 w/ a 23HP Kohler Courage engine.  When I changed the spark plugs this spring, I noticed one plug (left side when sitting) being bright white (looking very lean) and the other being a dry powdery black.  I put in new plugs and ran it for awhile and did another plug check and had same result.  What could be causing this?  Thanks in advance for your help,

Matt
ANSWER: This is tough!
Powdery (is that the right spelling?) black is always rich. Lean is lean.
You know both sides are running or you couldn't get "powdery" and "lean". The "powdery" has to have spark to bake the carbon onto the plug. The "lean" plug would be wet if it didn't have fire.
My first guess would be that the carb is leaking causing the powdery side and that you have a blown intake gasket on the "lean" side.
I suggest you clean the carb and change the oil to get rid of the"powdery" side, YOU MUST CHANGE THE OIL. If the carb is running rich or leaking it is contaminating your crankcase oil with fuel. Then let's worry about the "lean": side.

---------- FOLLOW-UP ----------

QUESTION: Thanks for the info.  I have the intake o-rings and carb gaskets on order and have oil, filter and new plugs.  I'm confused on cleaning the carb to stop the leaking.  How might it be leaking and where do I clean?
I started the motor last night (I did not remove any of the engine covers, guards, etc...) and sprayed carb cleaner in the area of the intake to see if the motor surged (indicating a leak).  There was no surge.  I will start the disassembly tonight.

Answer
Lets talk about carb basics. Basically your carb acts like the back of your toilet.
It has a float and a needle and seat.
When the carb fills with fuel the float (the ball in your toilet) rises shutting of the fuel flow.
When your toilet ball sticks you here water running and you jiggle the handle. Unfortunately you can't hear your carb leaking and it doesn't have a handle to jiggle.
Remove the carb and flip it  up side down. Remove the bowl and you will see the float. The float will have a needle attached. Remove the needle and inspect the "seat" the hole the needle seals against. this is where you need to concentrate your cleaning efforts.
While you have the bowl off blast every thing in sight with Gumout. You can use another brand but remember you get what you pay for. Now the most important part of a good carb clean... You have to replace the fuel lines and filter and thoroughly clean the tank. After you do all this do not install the fuel line to the carb yet. Crank the engine a few seconds until fuel runs freely. Then install the fuel line to the carb. This will purge any crap that may be in the fuel pump.
Remember you are pumping fuel here so put the Marlboro out and be careful.