What gas to use in my 1974 70HP LOOPER?

[chucko]

I have a 1974 70 HP johnson outboard. In the shop manual it says to run a regular, or premium leaded gasoline of not less that 94 octane. With todays fuel, should I be running a premium fuel in it? Does anyone know the compression ratio? Does this engine need one of the "low compression" headgaskets, or were they just for the 75HP model? Thank you.

 

[wilde1j]

Re: What gas to use in my 1974 70HP LOOPER?

Low compression deal is for underdevoped countries, where they have very poor quality fuels. You don't need it.

Regular 87 octane fuel is fine, higher octane is a waste of money and causes more deposit buildup.

 

[chucko]

Re: What gas to use in my 1974 70HP LOOPER?

Thanks Jim. The shop book says to use regular or premium, of at least 94 octane LEADED. Thats higher octane than whats available now. I suppose thats with the stock headgasket. Why would they say that? Ive seen a low compression gasket offered, but its very expensive. If the motor will run on 87 then theres no reason to run the special gasket, unless your out in the jungle somewhere? Right?!

 

[wilde1j]

Re: What gas to use in my 1974 70HP LOOPER?

The low compression option mostly likely includes new heads. 87 octane is fine for 99% of all outboards, except racing motors.