Fuel type? 87, 89, 91 octane?

[KG's Supra24]

Along the same topic ...

Do you fill the tank up when you put the boat away for the week? I have heard it is best to put the boat up with a full tank but i dont know what the benefit is. I have started doing this but simply because of one thread i read (maybe on wakeworld). Am i supposed to be doing this?

[ScottnAz]

I always store the boat full of gas. It's my understanding this limits the possibility of water condensation in the tank.
If the boat is stored and unused for more than 6 weeks, I add a fuel treatment to the tank before taking the boat out.

[JohnnyH]

I use 93 octane. If you can afford this kind of boat you should be able to afford the best fuel. The added expense is like what? A beer at the bar?? FYI, If you leave fuel in your tank for more than 2 wks the octane falls. So if your boat sits up for 2-3 wks that 87 octane is around 85..

[JoHNI_T]

I always store the boat full of gas. It's my understanding this limits the possibility of water condensation in the tank.
If the boat is stored and unused for more than 6 weeks, I add a fuel treatment to the tank before taking the boat out.

always store tanks full, like said above the more inside of the tank exposed allows for condensation when the tank heats and cools, if its filled to the neck there is no roon for moisture to form.

My dealer said to run regular 87 I did run 91 in my 06 5.7 325hp for 2 years then I switched to 87 and never noticed a difference, so I usually run 87 theese days,, and 87 is usually the freshest fuel.

[[email protected]]

Just bought an 89 supra and was wondering what gasoline to use? Can I fill it at a gas station/ with my tanks? Do I need to add any additives?

[NorCalPR]

87. I ran it that way in my 98 comp and sane way in my 96 brendella. Brother runs a new malibu with a 350, and he runs 87...

Unless its pinging, there is zero reason to run the 91 grade. Octane is there for pinging resistance.


You have to realize these motors were in trucks meant to run on nearly 0 octane...

Run 87 and be done with it. The rest is a waste (unless youre running some high performance motor like a 6.0 or a vette motor)

Sent from my SM-G920V using Tapatalk

[Sdc77]

In France we have 91, 91 +10% Ethanol (call E10) and 93.
I run E10 (91) for 4 years now without issue in the carbed 454.

[Moor]

IMO, you guys should be more concerned about running ethanol free gas in your boats over what octane rating your running. I won't get into the havoc that ethanol will wreak on your fuel system, google can tell you all about that.

If you fill up with 89 or better you shouldn't have any octane related issues. I've used 87 in my old sunsport in a pinch and didn't notice a difference. Modern fuel injected engines with electronic ignitions will retard the timing to prevent engine damage if lower than recommended octane is used. Older boats usually have lower compression engines and were designed to run on lower (89) octane.

[Southerngrounds]

100% gas NO ethanol!!! The octane rating becomes a factor on high compression motors. If you hear the motor ping or knock bump up the octane rating. It's most important to run 100% gas.

[korey]

Most of the marinas in the area and a few land based filling stations near our larger lakes (Cumberland and Dale Hollow in KY/TN) are carrying the Rec-90 (ethanol-free, 90 octane unleaded gasoline blend designed for use in recreational/marine engines). I've never believed in running any special gas in an old 10:1 compression ratio big block, but my boat LOVES this rec-90... Maybe it me subliminally justifying paying $3.89/gal on the water, but I swear the boat runs better on it!