No body asked but as a small engine mechanic for the last 20 years I'll chip in my two cents. This can be an issue that causes friends to end friendships. But here is my experience and reasons. I recommend IF E10 is used to use some type of stabilizer but if the unit is not used for 39 days or more drain the complete fuel system, yes that includes removing the carburetor bowl and emptying it or if it has a drain opening the drain and draining it. After all new equipment is shipped with no fuel in the tank or carburetor.
If you have E10 and don't use it within 30 days pour it in your car or truck and refill your cans and add a stabilizer to the fresh fuel. As for using high test mid grade or regular use what the manufacturer recommends. Remember they built it and have to stand behind the warranty. As for using high test why? There is only two reasons to do so. One it is the recommended fuel and you will have a lighter wallet after you leave the pump. Just a thought about high test also, It is refined for a higher octane, resistance to preignition which means it is harder to light could that make starting harder?
Many don't understand that there are at least two different blends of gasoline. Summer and winter. Summer blend has less volatiles in it so it does not evaporate too fast. Winter blend has more volatiles for those easy starts when it is cold. That is why the snow blower left sit all summer with gas in it will have more problems than a lawn mower left with gas in over the winter.
As for stabilizer don't care what you use I have seen all not work and really "gum up" the carburetor. The most important point is it is not a miracle product and still has a time limit mostly due to how the container was stored and I do not trust the length of storage time on the label!
A lot of fuel related issues are caused by storage conditions. You cannot expect a unsealed container sitting in the sun to keep fuel fresh as one tightly sealed sitting in a dark corner where the temperature rarely changes.
Need lawn mower gas? Find small engine fuel type and storage recommendations for max performance from the Briggs & Stratton Engines experts.
www.briggsandstratton.com
A primer on high-test gasoline: Is it for you?
www.roadandtrack.com
www.familylifeshare.com
Personally I prefer to use nonethanol gasoline but have had success with E10 also. But honestly I prefer diesel.
So there are my two cents. Give it some thought and do what you want to----You will anyway!!
Have a great day