GM Top End Cleaner?
Also, a suggestion. Because I can't get any of that good stuff here, I have been using water, as close to distilled as possible, and use a basketball needle as a restictor so that not too much can flow at one time.
So, disregard "my" statement about the plugs and O2's however I've still heard it can foul them if you have really heavy carbon buildup.
Really depends on what one you got.
I inserted the Top engine cleaner through here. This is the PCV. I used a small funnel and went slowly. The engine will sound like it is going to die. I had my brother hit the throttle slightly when it needed it. I left it overnight. When I started it in the morning and hit the gas, Holy ****!!. Smoke City. You may experience a little misfire until it is all burned through, but don't worry.
i'm sooo goin to smoke the naborhood up! whahahahaha lol The Best V8 Stories One Small Block at Time

Ive used GM Top Engine cleaner in my last 4 vehicles, and it has *never* looked like that.
Odd.
How many miles are on the motor? I did the seafoam at 60K and didn't have much smoke at all. I just didn't have much carbon buildup.
http://www.pipercubforum.com/marvel.htm Aviation fuel has a lot of lead in it and MMO helps keep it dissolved so it will burn away. WWII they had it in 50 gal drums to pour in the av fuel and it was all that kept the plugs from fouling out.
In the fuel system,: "Use the directions on the back for amount to put in the fuel per gallon of fuel (4 to 6 oz. per 10 gallons of fuel). MMO goes through the carburetor as a droplet, broken up like the fuel. When it enters the combustion chamber and the gasoline ignites, it is vaporized and soaks into the carbon buildup on cumbustion chamber walls, valve guides, around the valve stem, and on the spark plug. It soaks into the carbon and eventually loosens it up and it goes out the exhaust system."
32 0z at Wally World is $2.97, next time you fill up follow directions and put some in and it will clean your top end. When I change engine oil I add two cups MMO to keep dirt, varnish and gum dissolved so it gets caught by the oil filter.
for aircraft engine this says add 5 hours before oil change but I leave it in all the time. "Use one pint Marvel Mystery Oil about 5 hours before oil change. If screen type system, be sure to clean screen. Then, in the new oil, install one-half pint MMO. This cleans the carbon and sludge collected in the engine passages and crevices and hydraulic lifters, and stores it in the bottom of the oil kidney. Some will make it to the screen, but either place it will be removed at oil change."






