New build, general questions

But we were not assuming that, were we.......considering you already said ethanol free boat fuel.
I'm just answering why I use 89.
If I didn't I'd be using premium.
Worth the extra 70 cents to me even if it's redundant.

Pre-mixes use high-test base fuel- and I've had great luck with my saw and other lawn equipment using it.
When mixing 2 stroke gas ya got 2 months to use it before it starts to go bad
When mixing 2 stroke gas ya got 2 months to use it before it starts to go bad
I have had some premixed ethanol-free gas sealed in a jerry jug that had the motor rip just fine and dandy after being stored for 4 and 5 months.

Absolutely zero problem with proper airtight storage.
It's not necessarily "more heat" to ignite. It requires more input energy to break the molecular bonds of the longer hydrocarbon chains in the fuel in order to ignite. That input energy is heat. One way you add that energy in is by advancing the ignition timing, which increases combustion pressures, and thanks to the ideal gas law - temperatures. That is why high performance engines that require premium fuel have higher compression ratios and more aggressive ignition timing curves. If that same fuel is put into a low compression engine with a lazy timing curve it can cause incomplete combustion, or delayed combustion that leads to lower combustion pressures and slow flame fronts.

Pre-ignition is literally caused by the fuel igniting on it's own, usually due to high tempertures being enough to start breaking the covalent bonds of the shorter molecular chains on it's own. Aka, bang when you don't want bang. This is why higher octane fuel is used, it takes more energy to break those bonds, thus it doesn't ignite as easily in the same conditions.

So yes, it's true.
Great explanation ty.
I like to say in simple terms, low octane burns like a bang, high octane burns with a push.

low octane is more volatile, High octane is more stable.

Releasticly, if you don't spark knock with low octane, there is no reason to burn a higher grade.

But since oil kills octane, I would run at least 89.
Gotcha. Always good to get answers with an explanation instead of a yes or no. Makes it easier to understand. At least for me
Lol. Gotcha. To try and get the most out of the engine I do run premium gas and full synthetic oil. I have seen post where someone said the higher octane gas needs a higher temp to ignite. Not sure the truth behind that. Also I run an ngk b5hs plug
I run B7hs ,then again mines a Minarelli so it may be different...
Also I had seen a video where a guy was talking about exhausts and he said something along the lines that if you have fuel coming out of your carb when running it is a sign of your exhaust being too restricted. Is this true? I ended uup cutting tube shorter, the one inside the exhaust and to be honest I don't hear the four stroking nearly as much and it does seem to have a bit more power
Ok. I have tried a few plugs. As of late I have been running a b5hs but was told to absolutely do not use that in the phantom. It is a bit colder in the northern panhandle of WV so I haven't had issues but I am running an autolite 2974 right now. I have to use the shorter plug because the piston was hitting the plug