Should I use premium, unleaded or E10 petrol in my outboard?

Ultra-Premium (98 RON), Premium (95 RON), unleaded (91 RON) and E10 (ethanol blend) are all readily available but which one is best for your outboard?

Fuel for your outboard is rated according to the research octane number (RON).

The RON is a rating given to a fuel based on its ability to resist detonation.

Detonation is a violent explosion of the petrol in the combustion chamber as opposed to the very fast, controlled burn that was designed for your outboard. Detonation can cause serious and expensive damage to the pistons inside your engine. Detonation is more likely on high compression engines and these engines require the use of higher octane petrol. The best place to find the correct fuel to use for your outboard is in the specifications section of your owners’ manual.

Using petrol with a lower octane number than recommended may cause detonation and consequently possible serious and expensive engine damage.

Using petrol with a higher octane rating than that stated in the owners’ manual will not noticeably improve the performance of your outboard and may cause unforeseen problems.

E10 has a tremendous ability to absorb moisture from the surrounding environment and therefore is not generally recommended for use in the marine environment. This is expected to change as technology and regulation changes.

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- Reference 3

- Contact Cairns Outboard Service for your outboard service requirements.

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