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

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

WILL

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

The 87 will make more power in your boat

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

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

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

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.