jj3500

What do you guys use?

I still have this lawnmower that I pushed when I was 14 YO. Still runs...well too. Never really took meticulous care of it. Now I've have this 60" commercial lawnmower that I purchased brand new. Dealer "recommends" I use premium to get the most out of it.

Is there a marked noticeable difference over the long haul with premium to regular gas (just for this specific case of these mowers)?

Thanks for responses.

klx650a2

Depending on what kind of motor is in it (air cooled or liquid), premium fuel does burn cooler and that is what I use in my Stihl chainsaw and weedeater (manufacturer recommends 91 octane or higher). I would check the manual and use what it recommends.

jrs_dodge_diesel

I second that, check the manual.

dj_souvlaki

what brand and model is it?

I used to be in small engine repair. 2 strokes are a must to run premium fuel in. 4 stroke lawnmowers are fine using regular.

rockcrawler304

Could you please explain why?
Not doubting you, but never heard that before. I use the cheap stuff in my weedeater but wouldn't mind changing if it will help in the long run.

klx650a2

Anything 2 stroke I'd use premium... burns cooler...

Spooler

Med grade is what I use. Works good and burns cleaner then regular.

Fronty Owner

I run the cheap stuff in my 6 y/o Tecumseh.

rbrettctd

Briggs only recommendation is over 78 octane, at least that's what the manual for the old flat head opposed twins says.

bansh-eman

Generally 2 strokes need higher octane because they are more prone to pre-ignition due to carbon deposits

rockcrawler304

I guess I'll check the owners manual to see if there is a recommendation. If not. I will switch to the premium. It's not like I spend much on gas anyways. One gallon will last all summer of trimming

wannadiesel

In addition, the 2 stroke oil lowers the octane number of the fuel. That combined with poor cooling and high load can lead to detonation if you don't use high octane fuel to compensate.

On the old flathead 4-strokes, anything better than kerosene is good enough. Heck, if you are willing to use ether to start it they will run pretty well on about 25% diesel. Much past that and they knock under load. You don't need much octane to keep 6:1 compression happy. The late model OHV/OHC engines have higher compression but are still generally good on regular unleaded - but if the manual calls for premium you should use it. Air cooled engines are much more prone to detonation than liquid cooled because cylinder head temperatures run a lot hotter.

PistolWhipt

Probably best to use the premium .... we bought a brand new weed whacker ... maybe burned two tanks of fuel through it (cheap stuff) and now the thing has no compression. Mechanic said they see that all the time with the cheap gas. Too much alchohol (the gas ... not the operator).

Cheers,
PISTOL

Tedonlin150

If the fuel sold by you has 10 percent ethonol in it then i would try and find non-oxygenated gas. All small engines that run the non-oxygenated gas will last much longer.

TexasCTD

I always run premium in my gas cans.......and toyhauler fueling station. I just feel better running the higher octane in my ATVs, lawn mowers, weed eater, edger, chain saw, etc. Sometimes the gas will sit for a little while (2 to 3 months) before being used, so I figured it might help....I may be wrong in my thinking though. Never had a problem so far.

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