Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Firstly let me assure everyone here that I Always do research before I make statements on products. Always.

The product I linked may say fuel system cleaner on the label rather than the rather misleading mystery oil as on others but they are basically the same product.
The contents of both the product I linked and MMO and many other petrol system additives are basically the same
Approx 70% mineral oil
Approx 20% naptha solvent
And small percentages (approx 1% each) of other various chemical additions.
Some of the minor additions vary from product to product but at such low quantities will have very little effect.
Hope this helps dispel the Mystery
Cheers Dave.