I once had a Sunbeam Alpine straight 4 engine that had been sitting for 20 years when I bought it. Could not hand crank it no matter how hard I tried. I put a coupled tablespoons of Marvels Mystery Oil in each spark plug hole and the balance of the can in the oil. Let it sit for a week and it broke loose for me and I was able to start it up. Great stuff.
RSWiser

 

Seafoam (whale barf) is just light oil and a little bit of naptha.

http://www.seafoamsales.com/266-msdsseafoamen.html

Not in my engine!!!!!!!!!

 

Not in your engine? What's wrong with those ingredients? Naptha is just flammable liquids. It also has Isopropyl Alcohol(Isopropenol/Rubbing Alcohol) in it. Oil is just a lubricant..

On topic though..MMO is good stuff and +1 about making sure you have a quality filter with anti flow back

 

Snake oil!
People will buy anything!

 

Seafoam is snake oil?

 

Fresh gasoline has enough additives to remove varnish and keep it away. Carbon does not deposit where there is no combustion.

Adding it to the crankcase only dilutes the oil, and the solvent in it kills the lubrication properties, bearings and any parts that need to be lubricated suffer.

Adding it directly into the intake - the solvents do not have enough TIME to dissolve carbon deposits - plus it doesn't dissolve carbon anyway. Soak a carboned up piston in it - it doesn't do anything!
It can loosen carbon in a combustion chamber - the cooler LIQUID hits the hot carbon and shatters it, breaking it loose. Water, olive oil, grape juice, milk, etc will do the same thing! The danger there is a larger chunk of carbon can come loose, get stuck under a valve, holding it open, causing the piston to strike it, or holding it open long enough to burn the edges - or it can get stuck on the top of the piston, hitting the roof, breaking the piston.

Some folks are fooled into thinking the large amount of smoke from the tailpipe is carbon blown out of the cylinder, - catch some with a rag held behind the tailpipe- you'll see it's not. The smoke is just the oil burning off - olive oil, Marvel Oil, 10-30, etc. does the same thing! TRY IT!

But - the solvents in it MIGHT help as a fuel stabilizer when you store the vehicle. I'd rather use something designed for that.

As I said SNAKE OIL! P.T. Barnum was right! WD-40 proved you can make a fortune fooling people!