Mercruiser Fuel Requirements
Performance Product Technologies Questions & Answer Forum – Mercruiser Engine Fuel Requirements, Boat Engine Fuel Specifications, GM Marine Engine Fuel Specifications.
TOPIC: What is the minimum octane rating for Mercruiser engines?
Octane Rating
According to Mercruiser’s product information unlike some of the other Marine Engine Manufacturers they design and calibrate all of their engines to run on 87 octane fuel. This applies both for the carbureted product as well as the Electronic Fuel Injected (EFI) products. Note: The only engine from the Mercruiser business unit (not Mercruiser racing) that requires anything greater is the Emission Controlled (EC) Scorpion requires 89 octane.
Ethanol Limits
According to the same Mercruiser product information they are allowing up to 10% enthanol to be used in both the carbureted and EFI products.