502 mpi 95 octane
#1
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Hi. Hope some of you guys can help me. Here in Norway we only got 95 octane fuel and with a little Google search I read that my engine should only run on 87 octane. Does anyone have some advice how the I can run my engine safe and what kind of timing i should run. Today I have 8 deegre advance timing. Should I change this to earlier timing and should I remap the mefi 3. This is s 2000 mod with coolfuel system.
Regards Dan
Regards Dan
Last edited by danse78; 05-12-2018 at 09:21 PM.
#2
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Always ran 93 in mine with no issue. If anything, advance the timing 2 more degrees to 10 initial and leave the mefi tune stock. Retarding the timing would be a mistake with higher octane.
#3
#4

You likely ran across some very dated information regarding running 87 octane only. That was for VERY early MEFI 1 big blocks and was resolved with a MerCruiser Service Bulletin. Not an issue with your MEFI 3. Leave the tune alone. You will be fine.
#5
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Hi. Hope some of you guys can help me. Here in Norway we only got 95 octane fuel and with a little Google search I read that my engine should only run on 87 octane. Does anyone have some advice how the I can run my engine safe and what kind of timing i should run. Today I have 8 deegre advance timing. Should I change this to earlier timing and should I remap the mefi 3. This is s 2000 mod with coolfuel system.
Regards Dan
Regards Dan
#6
Charter Member # 55


The octane rating system in Europe is different from the US.
The US uses the AKI and the EU uses RON. https://en.wikipedia.org/wiki/Octane_rating
Just run your lower octane fuel. It will be about the same as 89 octane US and will be fine without doing any additional tuning.
The US uses the AKI and the EU uses RON. https://en.wikipedia.org/wiki/Octane_rating
Just run your lower octane fuel. It will be about the same as 89 octane US and will be fine without doing any additional tuning.
#9
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there is Merc OEM SB about issues caused with the higher octane and why not to use it for early and mid 1990 s big blocks EFI and 350 small block EFI
I ll see if I can find it rather than me typing it all out. Do not feel like typing a book a today.
I ll see if I can find it rather than me typing it all out. Do not feel like typing a book a today.
Last edited by BUP; 05-13-2018 at 03:40 PM.