PING! from carbon build-up?

Last week, I definitely heard the Merc go PING at mid-range throttle, it only did it once. Is this a pre-ignition symptom? I changed the plugs today, and each one seemed to have some gritty black deposits along the edge, by the tip. Not much on the face of the plug, just along one side, near the tips. All of the plugs looked the same. Some had a little bit more carbon than others, but all looked similar. The previous owner told me they needed to be changed. Are these deposits normal? If I run a can of B-12 through it, will it clear them out? -Chad

[FCnLa]

Pyro,
Carbon deposits can cause a hot spot causing preignition. I would not use B12 inside the engine because will take all the oil away. Use OMC engine tuner or some other equivalent and follow the directions on the label. I usally treat mine every 25 hours or less. The carbon will cause other problems beside depostits in the combustion chamber. It will accumualate in the ring lands on the pistons causing the rings to stick and loose compression which will cause unnormal wear of the cylinders and loss of power. If it has never been done before on your engine, I would shock treat it. Tilt the motor up as high as you can get it ( I have folded the trailer jack up to get the cylinders pointing straight up) and turning the motor to one side. I do one cylinder at a time, taking the plug out and rolling the piston to top dead center, so the engine tuner will not just run out of the ports. Then fill the cylinder with the engine tune and put the pug back in. Let it sit for several hours. Repeat this process on the rest of the cylinders and the same cylinder if necessary. It is time consuming, but it will work.

What kind of oil are you using or did the previous owner use? The cheaper oils do not comply with the TCW3 standards and will deposit more carbon. I only use synthetic oil now. As in Pennzoil avaliable at Wally World. OMC makes an additive called Carbon Guard which helps also. I'm sure Merc makes an equivalent. Hope I helped.

I was talking about BURNING a can of B12 through it, as a fuel additive. The mechanics who tend the boatdoctor.com web forum have reccommended it for removing carbon deposits, as well as clearing up gummed-up carbs. I will look into the engine tuner stuff. I think the prev. owner used good'ol Quicksilver Premium Plus, that's what I use. I am using stock oil injection, also.
http://albums.photopoint.com/j/View?u=1703110&a=13082832&p=49416308

[JTS Racing]

Don't remember which one off hand, but one of the jet ski folks makes a product called Ring Free. I've used it with no bad results and it did help clean the system some. Best results come from the newer oils. If you ever remove your heads, polish the chambers and area leading into the exhaust cavity. This will increase compression somewhat and keep it clean.

[Techno]

I wasn't going to mention this but...
read on the bass board that Blue marble oil cleaned the engine. They said it smoked at first because it was cleaning and after a few tanks it no longer smoked and the inside was clean. Your choice.

Where do I get it, and how do I use it? Add it to the fuel? how much? How do you guys like the picture at the top of the thread? Took that one on Monday. -Chad

[FCnLa]

Chad, try this:

http://www.bluemarbleoil.com/

It's is synthetic oil mixing at normal ratios, I assume. I have never used it, so I cannot verify its claims. I heard it was expensive. I have been told by many (including the Merc gooroos)to use the Pennzoil.

I do know this, Engine Tuner works. I have run it through my motor on the hose and you could actually see the carbon coming out of the motor and on to the ground!

Oh yea, nice pic. Sea ya.

As I said, I am running stock oil injection. Everyone I have read who talks about synthectics are also mixing, not injecting. Is it OK to use synthetics with stock injection? Is this just another type of 2-stroke oil, or is it a fuel additive with special purpose?