Premium Gas for 50hp & 7.5hp 2-Stroke Outboards

[sdh56]

I have 1981 vintage 2-stroke motors on my fishing boat. There is a 50 hp and 7.5 hp and they both run OK on the regular 87-octane, non-ethanol, gas available in my area. However, would there be a benefit to running 91-octane (Premium) gas in these motors? The 91-octane gas also does not contain ethanol.

The extra cost of Premium isn’t an issue, since I don’t burn very many gallons a year.

Also, are there any gasoline additives that would improve performance or benefit these old engines?

Thanks for your input.

 

[racerone]

Premium fuel is recommended simply for the reduced ethanol.-----Facts.-----Not all gasoline is the same.-------Not every state / country has the same rules / specifications for gasoline.-----Look at the specifications / shelf life of aviation fuel ---100LL ----For example.

 

[Alumarine]

The only benefit might be that there isn't any ethanol in the premium.
I always used regular fuel with ethanol in my 82 merc 50 and it ran well.
I ran it dry at the end of the year.

 

[roscoe]

No benefit with the premium.
In fact, some will argue it will damage your motors due to the

different burn deposits smell color temps etc what have you.

I run premium in all my motor because its the only non ethanol that I can get.

 

[jhande]

I've been an auto tech most of my life.
Really only need high octane if you get detonation (knocking) when running lower octane fuel.
The bad regarding ethanol is that it could quickly deteriorate rubber parts in older carburetors, such as the rubber tip on the needle valve or rubber seals on accelerator pumps, etc... But if the carbs have recently been rebuilt the replacement parts should be impervious to ethanol.

 

[sdh56]

Guys, thanks for the input regarding premium gas. Sounds like non-ethanol is the way to go.

 

[Texasmark]

I am currently running premium gasoline and NGK iridium plugs. Not about to change. Things didn't start out that way....they evolved.....for the better for me and my rig! Decided to give my little 2 and 4 stroke engines around the farm the same treatment......not about to change.