Which fuel to use for 2/s outboard

[krazyfisher]

Which should be used between unleaded and premium unleaded? does it make a difference with power or economy?

[griz066]

Regular is better economy on the pocket 8-)

[BaysideMarine]

Depends on the compression of your engine. If its an older hi comp engine you need to run premium fuel in order to not melt the pistons.

Later models with comps around 120 are engineered for regular unleaded. You can use either fuel in these engines.

Cheers,

Nicholas

[Roughasguts]

Premium is a pretty good cleaner and boosts the octane levels of fuel that has been around a little while.

So if i'm not using the boat every month it's the premium, if every week the regular.

[fartfish]

we use the new Shell ethanol fuel 5-10% ethanol then add another 10% ethanol plus a whole container of octane booster it makes our 2 stroke run like a rocket ship because of the extra power we can run a prop which is 1-2 pitches over the manufacturers recommendation. our 70hp 2 stroke now pulls about 52 mph when originally it only got 40 mph

[Roughasguts]

Interesting fartfish Is that ending up exspensive.
You might be better of trying 100/130 Aviation fuel that will make a motor crisp and responsive.

[Runaway_Bob]

I wonder id optimax would go alright with my 25hp Merc 2st

[revs57]

Ignore Fartfish...he's been red flagged from another thread and his post here reveals why...

I was running premium in the 150 efi (not optimax) merc for the first 70 hours. I believed I would get better economy and a cleaner burn. A couple of months back I decided that the price was hurting too much so swapped to regular unleaded. Over the past 50 hours since the swap I've noticed no drop off in performance and an I'm actually using less fuel...beats me

Cheers

rhys