http://speedsociety.com/does-seafoam-actually-work-in-a-car-with-proof/?gmg
That was just the spray into the intake. All that did was clear a little debris out of the throttle body. Nothing for the pistons/rings. After that step you have to pour Seafoam into each plug, and then work the pistons up and down one full cycle each, put the plug back in and let the Seafoam sit on the pistons and work. Then come back the next day and fire up the motor blowing out all the carbon. I promise the pistons will be shiny, I did it on my V4 Johnson and the pistons look like new on a 2001 2 stroke.
“Wailord”
1979 17’ Montauk
90 Johnson
Wilderness Ride 115