I hate to revisit this!

[ismellnownlatters]

But why do many folks with a stock china girl run over 87 octane? These engines are very low compression hect I even ,87 may be overkill. Is my thinking flawed?

 

[Wrench]

Mixing oil in the gas lowers the octane
So if you burn 91 octane in your 2 stroke it's like burning 87
Some guys use octane boost

 

[ismellnownlatters]

Good point

 

[Chainlube]

But why do many folks with a stock china girl run over 87 octane? These engines are very low compression hect I even ,87 may be overkill. Is my thinking flawed?

If you have non-ethanol fuel in your Hamlet/Town/City use that, doesn't matter the grade. Most guys around here use premium fuel because it's ethanol free that's all.

 

[Chainlube]

Ethanol fuel will destroy the crank seals.

 

[DAMIEN1307]

Most guys around here use premium fuel because it's ethanol free that's all.

That may be true in Canada, but here in the US, premium fuel also has ethanol in it.

Here in the US, you puposely have to ask for ethanol free gasoline at the few gas stations that actually still carry it.

 

[DAMIEN1307]

Ethanol fuel will destroy the crank seals.

Not to mention it also corrodes carburetor parts as well...lol.

 

[Sidewinder Jerry]

If you have non-ethanol fuel in your Hamlet/Town/City use, doesn't matter the grade. Most guys around here use premium fuel because it's ethanol-free that's all.

Maybe that might be true where you live. However, in most places in the US, if it doesn't have ethanol free or 100% gas on the pump then it's at least 10% ethanol regardless of the octane grade.

 

[Chainlube]

Maybe that might be true where you live. However, in most places in the US, if it doesn't have ethanol free or 100% gas on the pump then it's at least 10% ethanol regardless of the octane grade.

Here it says on the pump, 10/15%. Premium like 91 octane is 5%. 94 octane alchy free.

 

[ismellnownlatters]

The non ethanol stuff here is like 2 times more pricey as 87 octane and it has just one lonely pump that I never once see anyone use.so I worry it can be older