Wish I had a owners manual, grrrrrrrr. I have just acquired a 1997 volvo penta 3.0GS. Ser # 4110143168. Can I use regular 87octaine or do I have to use preimum?.........thanks
Just a note for the OP about what it says in that manual, so there's no confusion.
It specifies 93 Octane RON. RON stands for Research Octane Number, and isn't the standard used for the final octane number on U.S. fuel.
U.S. fuel octane is calculated by adding the Motor Octane number, and the Research Octane Number, then dividing by 2 (M+R/2 is what you see plastered on most gas pumps). So a U.S. graded fuel will have a lower assigned octane number than it's European equivalent. 93 RON octane should be roughly equivalent to 87-89 M+R/2 octane.
Thank you everyone, I did notice after reading the manual about the octane and it did confuse me. Thanks Don for the link, and Roger for the clarification about octane.
I have a 96 Four Winns with a 3.0 GS OMC (grey)/Volvo SX.
On the side of the valve cover it states min 92 Octane. I made the mistake of trying to run 87 in it once and it dieseled + run-on like a POS. A friend has the similar merc engine and can run 87 all day without issue.
The Volvo/OMC use a different head design with higher compression.