MMO = No Go

[AJB0009]

I have a 1997 McCulloch MAC 2818 string trimmer.
It has been incredibly reliable. A few years ago, I replaced the spark plug and the fuel line was rotted, so replaced it.
I think two years ago it finally got a carb kit as it wouldn't run right. This spring I put a new air cleaner element in.
I always use E0 gas (90 octane).
I bought a bottle of MMO to put some in my old Explorer. I thought that I would give my MAC a "treat" so I put an ounce in the gallon of gas/oil mix. It run like garbage. It was as if it was very rich. I had to keep it revved up or it would die. Finally, after a few minutes of trimming, it just quit, and I couldn't get it re-started.
At first, I thought maybe my old MAC finally bit the dust. After I thought for a minute, I remembered putting the MMO in. I really didn't think that was it, but that would be easy to try. I dumped all of the fuel out and mixed up a new gallon with just E0 and oil. After just a couple minutes of clearing the MMO laden fuel out of the lines and carb, it is back to running great again. Ran it for probably a half hour straight; purred like a kitten.
So much for the "treat".
I did also put about an ounce per gallon in my four stroke mowers and they don't seem to mind it at all.

 

[Brian123]

Sounds like you could benefit from using Trufuel 2 Cycle Mix

 

[Chris Meutsch]

After reading your story, I specifically went to MMO's website to see if they warned AGAINST use in 2-stroke motors; but they certainly don't.
Weird situation.

 

[BigCahuna]

When I fill my 5 gal gas can that's used for my mowers and such, I throw some mmo and carb cleaner in the can first, then fill the can. I'll use that gas in my can for my 2 stroke machines. Never had a problem and they start easy in the spring. I don't over do it with any additive, maybe that's some peoples problem why they have starting issues.,,,

 

[97prizm]

Some gas string trimmers seem more finicky than others. I don't think I've ever hax an issue with my Stihl.

 

[Warstud]

It wasn't designed to run on MMO

 

[tom slick]

MMO recommends 1/2 that dose in small engines

 

[Cujet]

I can't see the benefit of significantly thinning the oil in a two stroke, especially with MMO which will separate from the fuel along with the oil. Most people don't know that some of the oil comes out of suspension and migrates inside the crankcase, lubricating the lower end. A typical two stroke oil retains adequate viscosity in the lower end.

The higher the RPM, the faster the oil migrates through the engine.

http://hodakaforum.com/download/file.php?id=3219&sid=552b63800195a2a41b606ccd2ac3c735&mode=view

 

[jeepman3071]

I've used MMO before, but I wouldn't put it in a 2-stroke. It isn't needed.

 

[andyd]

How old was the mix you added the MMO to?

 

[repairman54]

Adding MMO to a correct oil mix is leaning out the fuel mixture. Yeah it runs better because in 2 strokes lean is mean. Any additional oil displaces the gasoline ratio. Fuel also cools pistons; oil is there for the bearings and rings. Folks can get by doing it as OPE don't run wide open as long as larger engines like in snowmobiles for example but it does happen. If you have ever holed a piston or burnt off the exhaust side edge of a piston you know what I'm talking about when I say lean is mean.