Regular gas or premium

[magoo's]

I have a 1979 55 Evin. Would you advise to use premium,and also what's your opinion on sythetic 2 stroke oil?

 

[NYBo]

Re: Regular gas or premium

Regular gas will be fine. You might experience less smoking with synthetic oil, but you'll have to try it out for yourself.

 

[H20Rat]

Re: Regular gas or premium

premium is for high performance engines that need it to avoid detonation. Using premium in an engine not designed for it actually gives you LESS power, not more.

(disclaimer, use whatever fuel doesn't have ethanol first, if that means premium, use premium!)

 

[cr2k]

Re: Regular gas or premium

Don't for get, everyone, in 1979 regular fuel was like 90 octane and now it's 87. It won't hurt it to run premium.

 

[bonz_d]

Re: Regular gas or premium

I've run 87 in my 1978 35hp for years w/o incidence, putting premium in it would be a waste of money and no need or benefit.

 

[rallyart]

Re: Regular gas or premium

cr2K, in times gone by the Octane rating was Research Octane which is often the higher of the two methods of rating Octane. They now use (R+M)/2 which averages Research and Motor Octane ratings. That's why it is lower now then back then. Regular gasoline then is pretty much the same as it is now.

 

[Oshkosh1]

Re: Regular gas or premium

Regular/Dino...synth may smoke a little less but will do nothing for an engine of that vintage other than that.

 

[xoibsurferx]

Re: Regular gas or premium

I was reading through a 1985 johnson manual my dad has and it says 69 ron (outside usa) and 67 in usa minimum. That seems ultra low to me.

 

[jayhanig]

Re: Regular gas or premium

Don't for get, everyone, in 1979 regular fuel was like 90 octane and now it's 87. It won't hurt it to run premium.

No, it won't hurt to run premium in an engine that doesn't require it, except in the wallet. It's pennies down the toilet. If your boat's engine doesn't knock, you don't need it. You can run it; you just don't need it.

 

[magoo's]

Re: Regular gas or premium

thanks Jay

 

[magoo's]

Re: Regular gas or premium

tthanks.will take your advise

 

[Captain Caveman]

Re: Regular gas or premium

No, it won't hurt to run premium in an engine that doesn't require it, except in the wallet. It's pennies down the toilet. If your boat's engine doesn't knock, you don't need it. You can run it; you just don't need it.

Not always the case. Some states put ethanol in all fuels, which can degrade your engine's internal fuel lines. If you are filling up in an ethanol zone, look for the non-ethanol gas which will mostly likely be the premium grade.

 

[bonz_d]

Re: Regular gas or premium

Not always the case. Some states put ethanol in all fuels, which can degrade your engine's internal fuel lines. .

All new USCG approved fuel line is ethanol resistant and shouldn't be an issue any longer. So if you're having problems with fuel lines then maybe it's time to change them.

 

[UncleWillie]

Re: Regular gas or premium

If a 55hp, 1979 OB motor hasn't already had 100 gallons of E-10 fuel run through it over the years;
It was kept in a museum.
If the fuel lines were going to disintegrate, they would have done it already.

 

[H20Rat]

Re: Regular gas or premium

If a 55hp, 1979 OB motor hasn't already had 100 gallons of E-10 fuel run through it over the years;
It was kept in a museum.
If the fuel lines were going to disintegrate, they would have done it already.

depends on your area... Non-ethanol fuel is easy to get in lots of places yet, in my state 87 and 91 octane are generally ethanol free. 89 octane, same price as 87, is e10 gas. I have yet to see a marina with ethanol fuel. (my state also has requirements that ethanol has to be marked at the pump)

 

[SigSaurP229]

Re: Regular gas or premium

I have run nothing but ethanol fuel for at least 5 years. The big but to that is that I replaced everyone of my fuel lines with ethanol resistant lines, and installed a water separator as well. Otherwise I have run straight 87 octane e 10 gas.

 

[ondarvr]

Re: Regular gas or premium

I've run E-10 for better than 20 years and have two motors from
the 60s and two from the seventies, I have only replaced the fuel lines on one. My newer motors have had no issues either.

 

[GA_Boater]

Re: Regular gas or premium

I'm in the use what spits out of the pump school. Lack of maintenance causes more problems than E10.

In answer to the OPs question, regular gas is fine and I use Pennzoil semi-synthetic TCW-3.

 

[DirtyOldBoat]

Re: Regular gas or premium

Lack of maintenance causes more problems than E10.

I agree. I think ethanol has become a scape goat for just about every fuel/carb related problem there is. Don't know why it's broke? ETHANOL did it! :facepalm:

 

[Captain Caveman]

Re: Regular gas or premium

All new USCG approved fuel line is ethanol resistant and shouldn't be an issue any longer. So if you're having problems with fuel lines then maybe it's time to change them.

What should be clarified in my statement is that letting ethanol gas sit unused in your fuel lines can cause degradation. Using it is not generally a problem if you keep it moving. If the OP doesn't plan to use his 1979 motor often, which could easily still have old fuel lines, he should consider non-ethanol fuel.