Gas to use?

All true as stated by Jonny Quest but not stated is when the computer senses detonation and pulls timing out of the engine it leaves you with less power and that could be at the same time you really want power.   Knock sensors can save your engine from any detonation damage which is fantastic but with a higher grade of fuel you would enjoy full power and not trigger the knock sensor to pull timing back..   I am not talking of jumping into race fuel and 110 octane. Just a jump from 85 to 87 or 87 to 89. Maybe in the extreme from 87 to 91 octane.   Sometimes one bump up keeps you at full power.   I run plain entry level gas in most of my cars and the boat unless I know I need to upgrade.   If you have to adjust your timing to eliminate pinging and detonation you are detuning the engine and leaving some performance on the table. I try and avoid ethanol blends in all my engines even though I know guys that have tuned for it and race with it.

Your wallet gets thinner!

The first day I had my 1980 SN, I put regular gas in it. It ran like crap after running great for the lake test. For then on, I always put in Mid Grade and sometime premium. It ran so bad on regular I never did that again.

Fill it up. Go to the lake a lot, ski, ride and enjoy so much that the gas does not have time to go bad. End of season last tankss lots of Marine Sta-Bil and run until it is in the entire system.

Orlando76 wrote: I'm on the water 3-5 days a week 13 months a year

Now that right there is impressive

My 89 has a label near gas filler warning not to use gasahol. Like others said above, if you modernize the fuel lines, etc, should not be a problem.

I'm on the water 3-5 days a week 13 months a year and use strictly 87-89 ethanol. No problems with carb nor efi. If it sat for 3+ months I'd shy away from ethanol if possible.

Might be a nice winter project to change out the rubber fuel lines especially if they are the originals and clean the anti siphon valve, the ethanol likes to eat at the older rubber lines.

Use what you can find. I try to run the non-oxy if I can, if I can`t find that I try to run Premium Unleaded.

All

I'm wondering if anyone can comment on what gas I should be putting in my '83 SN. The guy I bought it from said to only ever use non-ethanol fuel, but the first time I filled it up I couldn't find any around me so I used 93 (possibly ethanol) fuel.

So two questions:

1) Does it matter?

2) If it does, should I be worried about letting the current possibly ethanol fuel sit in my tank? Should I try and use it up ASAP? Drain it some other way? Should I bother using something like SeaFoam to clean out residue?

Thanks!

--Chris N.