This isn't exactly automotive, but seemed the best place to put this.

I bought a weedwhacker for the son-in-law yesterday, and some oil for 2 cycle engines. When I got home, I noticed a statement on the oil saying NOT to use it with E85 gas.

Why is this? Will it damage the engine? Will it not mix properly? Any ideas?

Sometimes you don't have a choice.

That said, my 5 year old, low-time weed whacker has run fine on the gas sold here in N/W Arizona.
The gas station pump does state that there is up to 10% methanol in the gasoline.

I've also found that the gasoline with methanol kills your autos gas mileage approx 10%.
Very much the same is true with Californias MTBE additive gasoline.


When I was drag racing with little brother we found that running straight alcohol was fairly corrosive to carbureted systems.
It attacked aluminum as well as some of the fiber washers that seal carburetors.

Not to mention that it took about twice as much (straight) alcohol to generate roughly the same amount of horsepower.

(The basic rule is 2.0-1 for racing and 1.7-1 for street use on straight alcohol.)

Advantages were, alcohols high octane rating allowed us to run a 15/1 compression ratio.
(As compared to a maximum of 11 or 12/1 compression ratio on racing gas and 10/1 compression ratio for premium gas at the pump.)

Dis-advantages were, alcohol made it hard to start the engine in cold weather.

We got to the point where we started the engine on racing gasoline and ran it until there was some heat in the heads and switched over to alcohol.
Interestingly, the 15/1 compression engine rattled and detonated (ping) on the best racing gas we could buy.

After the races, we had to purge the fuel system of alcohol by running straight racing gas.


So far, with the 10% methanol gasoline I've done nothing more than run the weed whacker tank dry between uses.
Said use being perhaps as many as 2-3 days in a row.

I did slip up last year and forgot to drain the tank, but had no problems starting up on the old gasoline.
It does run better on fresh gas.

Gas/oil mix is 50/1.


Is E85 a stronger mix of methanol to gas as compared to the 10% stuff we're using here?


And . . . what are you supposed to do if only E85 is available and you're not supposed to use it in your engine?

(Double post)

[edit on 7-6-2008 by Desert Dawg]

Thanks for the info on E85.

Shoulda looked it up my own self.

Just to dispel the "scariness" of E85 for one... it is Ethanol not methanol. Ethanol is completely fine to use in any car, it will not corrode metal in your fuel lines/fuel injectors. However... ethanol contains less energy (BTU's) in 1 gal than gasoline does per gallon. So you effectively have to "burn" more to keep the same air-fuel ratio. As far as the weed whacker goes you can use E85 in it.. however you would have to richen the mixture up otherwise it will run lean and get too hot. Any car can run on it if it's been tuned correctly. With fuel injection you normally need larger fuel injectors and possibly a higher volume fuel pump. You also need to tune the computer for the new fuel injectors and set Stoitch to approx 9.7:1 where gasoline is 14:1.

[edit on 9-6-2008 by bigshow]

Correct my spelling first... it is Stoich. Basically it is the optimum ratio of fuel to air for proper combustion of the fuel. So gasoline is 14.7 parts air to 1 part gasoline. Ethanol is 9.0 parts of air to 1 part of ethanol.

Originally posted by bigshow
Ethanol is completely fine to use in any car, it will not corrode metal in your fuel lines/fuel injectors.

Yes, it will. But the main concern is aluminum fuel tanks. Synthetic rubber is also not immune to premature hardening promoting leakage. So-called flex fuel vehicles use either anodized aluminum or stainless steel in places where bare metal contacts fuel, as well as teflon-lined fuel lines. There is also the issue of ethanol absorbing water with anecdotal evidence that this results in pitting in iron cylinder walls, however with this issue I would be most concerned with accelerated degradation of steel exhaust pipes.

Besides all that, I reason the big problem with 2-cycle motors is they typically blend their oil with fuel. Excessive alcohol in the oil will cause a loss of viscosity resulting in premature wear. Some FFVs recommend E85 rated oils to combat this problem, but I am not aware of any such options for 2-cycle. [this would explain why the warning is printed on the oil]


[edit on 10-6-2008 by apc]

I belong to a camaro (LS1) forum board and there are SEVERAL people who have been using E-85 in their non-flex fuel vehicles for several years without one problem. FYI an LS1 V-8 is an all aluminum engine 346 CI. One guy has a write up on how to configure the ECM to run on it and he lives in sweden where E-85 is much cheaper than gasoline. He has ran it for 4 years and 60000+ miles without an ounce of trouble.

That's nice. I guess all those big auto manufacturers have wasted millions of dollars in research and development on their vehicles. If only their engineers had read the postings on that Camaro message board, all that time and money would not have been wasted.

Regardless, the issue at hand is 2-cycle motors. I'm fairly confident in my conclusion that the reason for incompatibility is oil dilution. But then again those idiot automotive engineers seem to agree, so who knows.

There's no reason for a smartass reply. And I realize that my reply wasn't entirely about 2 cycle engines... however since no one is willing to "test" it then I see no reason not to try it as I will be converting all my lawn equipment to Ethanol and I expect no problems out of it. It seems the general consensus I get is everyone is scared of it... however many people think E-85 is Methanol which is a totally different animal.

There is every reason.

To succeed in such a venture you'll likely need to replace the piston or shave the head to up the compression and rejet. Also find some sort of oil blend that is not easily alcohol soluble. Maybe a fully synthetic with whatever additive the FFVs use. Seems like an awful lot of work just to save $0.50 per gallon in a weed whacker. I'd only try it on a junk motor first because if the oil solves you might not know it until the piston seizes.

I hear that E-85 can work. But i'm not sure...

It is actually possible. This one guy on YT ran a Homelite Chainsaw on E-85.
Saw the Video, appeared to work ok.

I may consider using a 50/50 mix of E-85 and Gasoline next year.

Can you guys tell me if it will work, and with the normal 50-1 Oil/Gas Ratio as well?

I use Amsoil Dominator Synthetic 2-Cycle Racing Oil- and i mix it with Sunoco 91, fyi.
Works fine in my 2-Cycle Engines, my STIHL Weedwacker and Poulan Chainsaw.
I put a bit of the Oil in a Echo Bottle every year and Ethanol Damage Prevention Fuel Stabilizer.
STIHLs and Echos require 91.
It says use 89 or higher on the 2-Cycle Oil Bottles.
In my Poulan Chainsaw, the 91/50-1 mix works almost as well as 87 or 89 and 40-1 mix (which is what i should use in it)



I use 89 in my Car (2008 Honda Accord- my dad sold it to me for 150usd because he wanted a new car)
Is it ok to use 89 in it? It requires 87 Regular, but i like how 89 sounds- the word.
And using a higher octane keeps the Engine a bit Cleaner from what i gather.

thebestoildotcom/AMSOILSynthetic2CycleOils/default.aspx

Some of these other ones will work as well as the one i use, but you'll need to possibly double the Ratio for the Saber Pro 100-1 2-Cycle Oil.

There are Gas Stations near me that sell E-85, according to the Net. Here's an alleged one:

Allentown, PA E85 Gas Station Locations

Allentown Service Plaza, 5052 Centronia Rd., Allentown, PA 18106

Allentown isn't exactly that close. It'll be kind of far from West Chester, which in Pennsylvania, where i live.

I know that there is a West Chester in NY as well.

I may consider calling them as well, perhaps, but next year. I'll ask them if they sell E-85 because i saw it on the Net. I won't say why i want E-85, cuzz that isn't any of their concern.

Regarding the Video from YT=

youtubedotcom/watch?v=SJTqc4w2bt0

If it says "Good", "Very Good" or Excellent then one CAN use any of those, and they'll work perfectly fine in Lawn Equipment and probly Snowblowers

Quote from Desert Dawg=

Is E85 a stronger mix of methanol to gas as compared to the 10% stuff we're using here?


Wrong bro. E-85 is NOT Methanol. It's roughly a 85/15 mix of Gasoline & Ethanol.

I havent heard of M-85 before, but it might exist.... not sure though.

Ethanol is mildly corrosive to the Engine and Rubber Parts.
Methanol was once used at a 5% ratio and it was more corrosive.