So I started having problems with my Echo brand string trimmer. The thing is less than a year old. I could get it to start and run for a minute or two, then it would sputter and lose power. I could limp it along on half-choke for another few minutes, then it would up and quit.

So I take it to a small engine shop and drop it off. It's a major shop in town, and also a dealer of small gas-powered equipment. I had forgotten about it for a week or so, but I just called them up today to see what was up with it.

Turns out that they'd tried to rebuild the carb, but that didn't fix it, so they put a new carburetor in the thing. The guy on the phone told me that the low-octane gas has additives in it that the high-octane gas doesn't have, and that these additives will damage carbs.

I didn't really believe that, though I suppose it could be true. There's crap in all the gas these days, no matter what the octane rating. I had been running 87-octane in it and I learned that that's a no-no, I should be running Premium... okay, fine, but that would hurt the piston and cylinder, not the carb.

The thing probably had only five or six tanks of gas through it in its entire lifetime, and I don't see how the fuel could have caused it to go south so fast. I think someone may be trying to snooker me.

-AaronB

I have found that by using gas with no ethanol my small engines such as string trimmers and chainsaws have run noticeably better. Most premiums have no ethanol, but there is a website that will tell you where to get no ethanol gas in your area. The running problems I have had are exactly what you describe. I don't think it has anything to do with octane, and everything to do with alcohol in the gas.

Gasahol ate the fuel lines in the tank of my trimmer. Probably fine particles from these messed with the carb. After replacing fuel lines blowing out the carb and running a couple of tanks of real gas/oil mix the trimmer runs correctly.

I've been using an Echo brand string trimmer for 5-6 years without any problem using the same gas I put in my car (87+whatever they add). On the other hand, I have an Echo blower bought in 2010 that worked fine for a year, now will not start and I haven't addressed that yet.

Even the good name-brand stations in my neck of the woods have ethanol in the gas... even the premium gas.

They sell steel cans of premix at the hardware store. I may decide to go with that.

-AaronB

The very FIRST thing I do whenever I buy a new small-engine implement is rip out the @#$%^&*! spark arrestor. It's a little screen over the muffler exhaust port that will clog up with gunk after a couple hours of running any 2-cycle engine. The back pressure will then make the engine run like crap and be difficult or impossible to start cold.

The @#$%^&*! government requires spark arrestors on any small engine regardless of where it's sold or whether or not it's needed, so dealers will not remove them, but it's no trick to do it yourself in most cases.

I make gasoline for a living working on a FCCU unit in a refinery, I also blend it into a final product before it goes on the pipeline, that man is
BSing you.