John Deere 400 Fuel Recommendation

[bob48]

The JD 400 Owner's Manual (1975-1983) recommends 85+ octane fuel but NO high-test gasoline.
Thinking out loud that 87 octane with ethanol might not be good for seals,
would 91 octane (no ethanol) be okay to use even though I consider 91 octane a high-test gasoline?

-bob

 

[Monster5601]

91 octane is considered by most to be mid-grade. The ethanol around me is rated at 90 octane and I use ethonal-free gasoline in all my small engines from the small two cycles trimmers up to the 4 cycle leaf vacs and even in my four stroke outboard motors.

 

[Roadworthy]

I don't know what seals ethanol might eat - perhaps in your carburetor - but I know from experience it will eat flexible neoprene fuel lines. There is a newer neoprene formulation to stop that but any non ethanol fuel would be better overall. Ethanol does retain moisture in your fuel as well and may speed rusting in your gas tank.

 

[bob48]

Monster5601 and Roadworthy - Thank you for your very quick feedback! I was hoping that the 91 octane/no ethanol was the answer. I am still working on this antique John Deere 400, so will frequent this website.

 

[Robin Veerman]

recommends 85+ octane fuel but NO high-test gasoline

If it’s a recommendation that’s all it is, a recommendation. I don’t think it “forbids” high-test, although it’s a little slower ignition to prevent pre-ignition. Ethanol in your fuel would be more of an issue, especially if it would see infrequent use. Ethanol wasn’t an issue when the OEM recommended 85 Octane only.

 

[bob48]

Thanks Robin - I am now using the 91 octane-No ethanol; and seems to working fine.

 

[Robin Veerman]

Perfect. However, be sure that it’s labeled as no E gas. Being Super grade doesn’t automatically mean no E.

 

[bob48]

Yes, I will check it is NO Ethanol!