Re: "SeaFoam" and Gas String Trimmer tune-up.
Curious as to what this SeaFoam "miracle product" was all about, I checked into the ingredients by looking up the manufacturers mandatory MSDS (Material Safety Data Sheet) on this product. I found that it contains: "Pale Oil" 40-60% (by weight), "Naptha" 25-35%, "IPA" 10-20%. "Pale Oil" is simply another name for common mineral oil, the same stuff that is found in most engine oils (without the additives). "Naptha" aka VM&P (Varnish Makers and Painters) naptha, is what is more commonly known as "gasoline" without the additives, aka "white gas". "IPA" is simply Isopropanol which is more commonly known as Isopropyl Alcohol or "Rubbing Alcohol" (diluted). All the "degumming" and cleaning effects of this compound can be attributed to the solvent effect of the naphtha and the Isopropanol. Obviously, since your gas tank has a copious amount of gasoline already in it, adding more is not likely to accomplish anything. The real solvent effect is in the Isopropanol which in 10-20% concentration, is likely to have little solvent effect upon gum, varnish, and other petroleum oxidation products unless you use it "straight". Currently, most "oxygenated fuels" contain around 10% Ethanol (another alcohol) which is also an excellent solvent. So adding more alcohol to fuel that already contains another form of alcohol is not likely to be particularly beneficial. Also, there are many anecdotal accounts of small engine repairmen blaming the deterioration of internal carburetor rubber diaphrams and other such parts, on the effects of alcohol and other additives in current gasoline formulations.
The best way that I know of to properly service a diaphragm type small engine carburetor, is to buy a carburetor rebuild kit and rebuild the carburetor. The necessary tools are minimal and the only other thing required would be instructions (see your local library), and a can of carburetor cleaner from your local wally world or auto parts supplier. A wrench to remove the carburetor, and a couple of screwdrivers to disassemble the thing is usually all that is required. The diaphragm in a small engine carburetor acts by using crankcase pressure pulses to pump gas from the tank to the carburetor. They are thin and really flimsy. They also do not last forever. Good luck.
