Fuel for a 50's motor.

[DeepCMark58A]

Going to be running a 1959 Mark 58 next summer should I run Av gas, race gas, or will the new gas run the motor without wrecking seals and gaskets.

 

[Frank Acampora]

Back in the '50s they used to recommend regular or unleaded fuel. Premium (or "ethyl") contained higher amounts of tetraethyl lead to boost octane and this compound released real lead after the four ethyl groups (think ethanol) were burned. This lead tended to plug exhaust ports. Today, no pump gas contains lead so regular 87 octane is sufficient. Yeah, eventually the 10% ethanol may affect your fuel lines but on an engine that old you will be replacing them anyway.

I know that Mercury used to advertise "Fully Jeweled Power" but I don't know what bearings that engine had. SO: Investigate the fuel/oil ratio necessary for that engine. It could be 25 to 1 or even as high as 16 to 1. Better to be safe than sorry.

 

[DeepCMark58A]

I spent a good hour or more talking to the guy I bought the motor from and he recommended 25-1 Amsoil synthetic for the oil mix.

 

[Chinewalker]

I just finished building this 1950-ish Mercury KF7 over the weekend and put it through its paces on Sunday. I run 25:1 in my non-racing Mercs of that era, regular Evinrude oil (Shhhh!) and 87 octane pump gas. Nothing wrong with running Amsoil in your old Merc, and you are correct to keep the ratio at "vintage" levels, regardless of the newer oils being better. Ain't nothing like an ol' Merc!

 

[DeepCMark58A]

Thanks for the info that motor is a beaut.

 

[Scott Danforth]

regular Evinrude oil (Shhhh!)

Blasphemy!

:lol:

 

[JimS123]

I've been running outboards for over 50 years and have never found a better oil than Evinrude XD-50. Not even the syns or semi-syns.

Yes, run the ratio the same as what was originally recommended in 1959.

The only issue I've ever had with E10 is with the laquered cork gas gage floats in the portable tanks. Replace that with syn rubber float for $1.25 and you'll be fine.

 

[DeepCMark58A]

I thought that with the new gas that metal gas cans were not recommended?

 

[Chinewalker]

I actually prefer the metal tanks. Knock on wood, I have yet to have an issue with ethanol in any of my rigs. Part of that I attribute to using the old steel tanks. They aren't freely vented like some of the plastic ones are, so they're less apt to draw moisture from the atmosphere over warm day/cool night cycling.

 

[mla2ofus]

The only issue I've ever had with E10 is with the laquered cork gas gage floats in the portable tanks. Replace that with syn rubber float for $1.25 and you'll be fine.

I went thru the same thing w/ my old 'Rude tank. Adapted the float from a P/U tank to it.
Mike

 

[JimS123]

I thought that with the new gas that metal gas cans were not recommended?

Somebody always has the wrong idea no matter what the topic is.

Ethanol in itself never hurt a metal tank. In fact it is probably advantageous bevause it will help clean out all the old crud. Rust due to moisture is the enemy of steel. Ethanol combines with moisture to eliminate it. With all the issues with the new plastic tanks, if you can find a rust free old tank go for it.

 

[JimS123]

I actually prefer the metal tanks. Knock on wood, I have yet to have an issue with ethanol in any of my rigs. Part of that I attribute to using the old steel tanks. They aren't freely vented like some of the plastic ones are, so they're less apt to draw moisture from the atmosphere over warm day/cool night cycling.

The operative word is "freely". They ARE vented properly. I have OEM tanks from 1953, 1970 and 1984 and all look like new inside.

 

[alanfox55]

I recently purchased an OMC and Johnson steel tank for $10. The OMC looks clean inside but the Johnson is covered with rust dust. I read that vinegar would clean it up so I'm going to try that.