co1615

Hello,

Have any of you come across any small engines that run better on one type of gas over another? 87 vs 93 octane, ethanol vs no ethanol etc...

Thanks,
Trent

Live Oak

In my opinion. IF you can find it. Gasoline that has NO ethanol or any other alcohol is probably your best bet. The octane rating is really not that important as most small gas engines have a compression ratio that works best with 87 octane fuels.

co1615

Thanks!

Had a customer call in and said he runs 93 in all his equipment. The particular engine in question was a Subaru EX17. I didn't think that small engines benefitted from the increased octane?

Cannuck-elhead

Modern OHV valve engines do need slightly better octane than the old standard L-head or side valve engines did.

That said the 'old' engines got on just fine with anything over about 77 octane fuel, today's OHV engines though need a minimum of about 83, although 87 is probably safer for preventing carbon build-up.

Higher octane fuel is a double-edged sword. It will start and run better, but it will also run hotter, not a great thing for an air-cooled engine.

The other factor though is, as the ole' Chief mentioned, alcohol.

In a lot of areas 'high octane' fuel still isn't blended with Ethanol or other alcohols.

In the long run, I'd much rather run high octane gas that was NOT mixed with alcohol than low octane fuel that WAS mixed with alcohol.

Ethanol and the other alcohols are 'hydroscopic', meaning they very readily absorb water into solution. When you blend Etahnol into gasoline, now the entire fuel mixture likes to absorb water. This is not a great thing for engines that can be fussy about starting to begin with.

co1615

OK, thanks for the replies!

magfarm

I second the comment about avoiding ethanol fuel if at all possible. If not, a good fuel additive/intake cleaner can help.

__________________
Allan
http://www.superiorsyntheticsonline.com

indypower

The manufacturers recomend 87 octane. They also say their engines run fine with up to 10% ethonal, which is what is in most pump gas today. Using 93 octane is just a waste of $$$ and has no benneifit. I personally have found that using Shell gas with nitrogen works great!! I use it in my truck and get better gas mileage. The nitrogen cleans valves & head.