Originally Posted By: Reddy45
I physically cleaned the carb on my 2-stroke weed whacker, but I noticed carbon buildup on the top of the piston when I had the spark plug off.
The motor runs fine and screams like a typical 2-stroke, but I just wonder if I can really clean out the cylinder with Seafoam since I have a can sitting around at home with no purpose currently.
I've used SeaFoam for cleaning the combustion chambers on a couple outboard engines and an old rough running two stroke Tecumseh powered ice auger. I poured the SeaFoam into a squeeze bottle and ran the engines at moderate rpms and squeezed bursts of SeaFoam into the carb. I'd spray enough in to cause the engine to stumble and allow it to regain normal operation. I did that a few times the gave it a continuous burst until the engine stalled. Then I squeezed a burst into each spark plug hole, put the plugs back in and allowed it to sit for a bit to get the liquid into the rings. After a minute or two, I place the engine with spark plugs down to allow everything to drain into the combustion chamber and let them sit overnight. The next day, I fired them up. There was a great deal of white smoke created and initially lumpy running engine which smoothed out as the smoke diminished. Each engine was given a good run and performance was the same other than the ice auger engine started and ran better for some reason. It hadn't been used for years so it was probably just getting better carburetion from fresh fuel/Seafoam running through it. Can't say for sure.
Visible inspection of the piston crowns through the spark plug holes showed areas of bare aluminum that where once totally black. It appeared that it had lifted some of the carbon there and likely off of the cylinder head as well. To me, the small accumulations of carbon on the piston crown and cylinder head are of no real consequence. The primary cleaning objective for me is rings. I've pulled apart a few old two cycle engines to find the rings virtually useless due to carbon being baked into the grooves. If Seafoam contributes to keeping the ring free, that's good enough for me. Compression tests that I've done have all shown that the engines are good, most in the 120 psi range. Can't say that's because of the Seafoam but overall, it doesn't seem to hurt.
The down side of SeaFoam is the exorbitant price. It's up around $14.00/can here. In view of the fact that there are no tests or measurements that I'm aware of to confirm that it works, it's a little pricey for a leap of faith....
Nonetheless, I keep a can around for mixing with the fuel.