What is the typical oil-to-gas ratio for an outboard boat engine?

The gas-to-oil ratio for a typical two-stroke outboard boat engine is 50 parts of gas for each part of oil. During the engine break-in period, the gas-to-oil specification is typically about half of that, or approximately 25 parts of gas to 1 part of oil.

Many two-stroke engines for smaller pieces of machinery, such as engines in chainsaws or trimmers, use a 40:1 oil to gas ratio. It is important to consult the owner's manual for any piece of machinery that requires a premixed solution of oil and gas to operate, particularly with regard to boat motors that were purchased used or have been subject to heavy duress.