So ur saying you never put anything in your tank except 87 octane pump gas ...bottem line is it's a lawn mower engine Do you put the right octane gas in your mower? Probley not you Probley just put whatever you got in the garage in....just saying it ain't gotta be 87. & with a few mods why wouldn't you run higher octane ...it's not like it's gunna hurt
I don't have a lawn mower. I live in the desert.
My engines are flathead Briggs or Tecumseh, or two stroke Clinton, and West Bend. All of those engines use "regular," as is recommended for the stock configuration GX based engine in the original post.
The only gasoline in my garage is regular, or regular with Burris two stroke pre-mix.
My 1967 440 RB engine is 10.1:1 and it receives mid grade, and alcohol stabilizer.
The higher the octane rating is, the more heat and compression required to burn the fuel. So running higher octane fuel in a stock, or even slightly modified engine will result in decreased performance.
It is generally accepted that CR's of 11:1 and higher are the threshold for considering higher octane fuels.
So no, I don't just dump anything in my engines.