Use of Premium Gas in Brand New Lawnmower?

Rivets said:

I think you should do a little more research, because premium fuel does not burn noticeable hot than regular. It is designed to burn slower, to resist knocking and pre detonation in the cylinder.

You say there are no non ethanol stations in your area. According to this registry there are 284 in NC.
Ethanol-free gas stations in the U.S. and Canada

Please make me smarter, and tell me which engine manufacturer says not to use premium.

I agree with you on one thing, premium is not going to make your engine run better. No one ever said that. Want I am saying is that in my experience of over 40 years working on engines, using non ethanol fuel will save the owners of today's small engines money, and lost time.

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Slow your role there..I'm not a small engine expert like you are probably..let's just be sure we're straight on that. Plus I am not within a reasonable driving distance to a station in my location that sells non ethanol gas I should have said. According to what I have read online, non ethanol gas IS best to use and I was saying what the majority consensus was online about using premium fuel in a lawn mower small engine. I also just quoted what my owners manual said about NOT using Premium Fuel. I'm going to try and attach a few pics of what it says..

High octane rating does not necessarily mean the gasoline contains less ethanol. In fact, the adding of ethanol can actually raise the octane number and this is one of the reasons some gasoline contains up to 20% ethanol. The E85 fuel (85% ethanol) has an octane rating around 95, and the pure ethanol, close to 100.

detett1560 said:

Slow your role there..I'm not a small engine expert like you are probably..let's just be sure we're straight on that. Plus I am not within a reasonable driving distance to a station in my location that sells non ethanol gas I should have said. According to what I have read online, non ethanol gas IS best to use and I was saying what the majority consensus was online about using premium fuel in a lawn mower small engine. I also just quoted what my owners manual said about NOT using Premium Fuel. I'm going to try and attach a few pics of what it says..

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I use Premium Gas in all my mowers and equipment 93 octane, always have and wont run anything else. All my manuals say For best results use only clean, fresh, unleaded gasoline with an octane rating of 87 or higher (R+M)2 rating method. Not any of my manuals say you can't use premium gas.

Most of the non ethanol fuels produced today are for the premium fuels. Very seldom will you find an 87 octane fuel that is non ethanol. That's why I said we recommend running premium non ethanol fuels. Higher octane fuels burn slower which resists knocking. Because they burn slower and engines are running at higher RPM's there will be more unburnt fuel leaving the cylinder. This unburnt fuel actually allows the engine to run cooler, not hotter. Your manual says nothing about running premium fuel, it talks about not running fuel with a high ethanol content.

Rivets said:

Most of the non ethanol fuels produced today are for the premium fuels. Very seldom will you find an 87 octane fuel that is non ethanol. That's why I said we recommend running premium non ethanol fuels. Higher octane fuels burn slower which resists knocking. Because they burn slower and engines are running at higher RPM's there will be more unburnt fuel leaving the cylinder. This unburnt fuel actually allows the engine to run cooler, not hotter. Your manual says nothing about running premium fuel, it talks about not running fuel with a high ethanol content.

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Yeah it talks about not using %15 or E85 or methanol.

To Rivets--thx for the website... there I found an app for that, & I used it to locate an Ethanol free gas 1.7mi away... I couldn't recall what bad stuff they said would happen with the "wrong" fuel, & someone put it in writing--excellent, Thx!

Geez, I wonder what Ethanol does to my car!! I think, with any engine, you use what works best... what sputters the least, & runs smoothest. Getting to know YOUR engine is what it's all about...I know I learned something here

Just cuts down on gas milage. You put it through your car so fast that it does not affect any of the parts. Try a couple of tanks of the non ethanol in your car, I'll bet the miles per gallon go up.

Premium gas is needed for high compression engines to prevent knocking and also in low emission engines which tend to run lean and with more spark advance. Lawn mower engines tend to be low compression and tuned less radically, so they don't need high octane gas to operate properly. There is no gas consumption advantage to using premium gas in an engine that is tuned to use regular gas. However, using high octane gas won't harm your engine either. All it will do is lighten your wallet.

As to ethanol, it's pretty much a fact of life in most areas on the USA, and used in all octane grades. I use an ethanol treatment such as Sta-Bil or Ethanol Shield in my gas can when I fill up, and it keeps the gas from breaking down for at least 6 months. In the winter when I don't use my mower for months I simply shut off the fuel petcock and drain the carb float bowl.

Rivets said:

Most of the non ethanol fuels produced today are for the premium fuels. Very seldom will you find an 87 octane fuel that is non ethanol. That's why I said we recommend running premium non ethanol fuels. Higher octane fuels burn slower which resists knocking. Because they burn slower and engines are running at higher RPM's there will be more unburnt fuel leaving the cylinder. This unburnt fuel actually allows the engine to run cooler, not hotter. Your manual says nothing about running premium fuel, it talks about not running fuel with a high ethanol content.

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Ric said:

Yeah it talks about not using %15 or E85 or methanol.

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Thanks Rivets, Ric, Mike, Snapper, and all the rest of you guys. Rivets you are right...for some insane reason I was thinking "Premium Fuel" the manual is referring to was simply the higher grade at the pump! I understand now what it is referring to. Thanks for educating me on this subject!! :ashamed:

For what its worth, I used 91 Octane in the mower, ethanol and all added to it I guess lol It was the first time I used the mower since I bought it. I added the oil, filled it with gas and it started on the first pull :biggrin: I had almost 2 feet tall grass to tackle as we've had alot of rain lately. The mower never missed a beat...it has a strong self propelled pull also I was surprised to find out. My back yard slopes at the rear. I really was impressed how it performed in all of that wet tall grass. One problem I did notice was the grass bag design. It has clips to secure it to its frame and there is a quarter inch gap at the bottom that blows out fine dust until it starts to fill with grass. Otherwise it fills and holds ALOT of grass.

Thanks again Guys for all the feedback! I really appreciate it! :thumbsup: