Octane requirements for Merc 500's

johnnywhip · 07-07-2006, 01:39 PM

Whats the suggested min octane for the Merc 500 hp efi, in my 2001 35 Lightning?? At our lake I see gas from 87 to 110. thanks, whip

BAJA WILL · 07-07-2006, 02:53 PM

I run 87 oct have 400 hours never one problem, as long as their stock just 87 is fine.

WILL

FeverMike · 07-07-2006, 04:19 PM

Yep, 87 octane. More octane and you are wasting your money and possibly losing power.

TeamTaboo · 07-07-2006, 04:27 PM

The 87 will make more power in your boat

carney · 07-07-2006, 06:38 PM

I put 110 in a stock 502 carb and It had no top and at all.

TeamTaboo · 07-07-2006, 09:50 PM

The lower Octane fuels burn faster, makes more power in low/comp engines. The high octane fuels burn slower for the high/compression motors.

GOODT · 07-07-2006, 09:55 PM

they will run on 87 with no problems ( the beauty of efi computers ) but prefer 89- 93

Viaqua · 07-10-2006, 10:29 AM

I run 87 all the time, 530 hrs-no issues but when I can only find 93, it blackens the transom like crazy. Burns ok, runs ok-the computer changes your advance when it reads the difference but makes a mess of things.

500 EFI's-stock setup on a 38 Lightning.