All two stroke outboards require an oil / fuel mixture when being used. The oil lubricates the crankcase bearings, pistons, rings etc. It is vital this procedure is carried out to prevent the outboard seizing.

Some outboards have a separate tank for the oil which will either be an internal tank attached to the outboard under its hood or an external tank. This is known as oil injected system which will require filling before or after each use.

Other models require the user to mix the oil and fuel together in the outboard’s main fuel tank each time the fuel tank is topped up (this is known as a premix model) In addition to this you will need to know if your outboard’s oil/fuel mixture is either 50:1 or 100:1 so that the correct amount of oil is poured into the fuel tank. Too much oil can result in the spark plugs blackening up, the outboard running rough or very smoky. The table below will give you the correct measurements to hopefully prevent any problems.

Oil Fuel mixture chart

Fuel Amount (Litres) 50 : 1 Ratio (ml) 100 : 1 Ratio (ml)
5 L 100 ml 50 ml
10 L 200 ml 100 ml
15 L 300 ml 150 ml
20 L 400 ml 200 ml
25 L 500 ml 250 ml
30 L 600 ml 300 ml

For more information please call: 01475 744 555.

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