Echo string trimmer mix problem

[1977c10phxdriver]

I have a 21cc Echo string trimmer now about a year old. I've been running Mobil syn 2cycle oil and so far so good. Problem is, it refuses to go into a full 2 cycle under any load, any condition! I'm sure it's using too much fuel since it's always in a 4 cyle mode. I've looked the carb over and over and do NOT see any mix screws. Is there any way to lean this thing out a tad? It will try to break into the 2 cylce "sometimes" but never quite makes it. Any ideas on this thing?

Mark

 

[Slick 55]

What do you mean by a "full 2 cycle" mode?

 

[LarryL]

Get it serviced by someone that knows what they are doing. Then just run it without messing with the adjustments. My Echo is over six years old and has never been adjusted. I buy the service kit, plug, fuel filter and air filter, and change it often. I also use Red Line racing two-stroke oil at about 50 or 60 to one. It gets used about 1-2 hours a week and a lot of it is cutting high growth, not just trimming easy stuff. I go through about two of those heads a year, that dispense the line. The key is to get it adjusted right and leave it alone. It's money well invested.

 

[Cujet]

For those who don't know, it is quite common for 2 stroke engines to run in a mode that is termed 4 stroking. It is usually caused by overly rich mixtures. It also could be spark plug related.

In any case, the Echo carb may (not all have this) have an adjustment screw under a pressed in cap on the passageway on the bottom. The cap is about 0.200 inches in diameter.

Try a new plug. Also, try more oil in a small batch to lean out the f/a mixture.

Good luck.

Chris

 

[1977c10phxdriver]

Thanks Chris,, I'll take a look tomorrow. I was hoping after it broke in some, it would straighten out but it didn't.

Mark

 

[1977c10phxdriver]

Hmm, what is a "full 2 cycle"? Well, it its running too rich, it won't run like its designed to, it will fire every other stroke, not achieving full power and rpm. Maybe you remember flying model airplanes as a kid. The Cox .049 engine is a good example. If its too rich, it runs poorly, spits extra fuel and oil and would not get off the ground. If you turned in the mix screw, it would all of a sudden try to speed up and run right, then a tad more and bingo!!! That sucker wound up and hauled a** and flew like it was supposed too. Thats what I meen by a "full 2 cycle."

If its "adjusted" properly, it will 2 cycle and reach its power band and decent rpm.

"the key is to get it adjusted right and leave it alone".........True, but how does one "adjust" a non-adjustable carb? LOL The trimmer gets used about 10 minutes a week. Guess I"ll have to call Echo and see what they say.

I thought I remembered someone mentioning a little tiny screw inside the throttle blade shaft, looked but could not see anything in the hole, although the shaft IS hollow! Maybe its in there somewhere.

Mark

 

[1977c10phxdriver]

Well, I have some info on the "non-adjustable" carb on my trimmer. I emailed a certain company and asked for assistance on my problem. A certain person CALLED me from above non-named company at 7:30 this morning. He told me that the carb is basically "non-adjustable" by John Q. public but can be "adjusted" by a "professional". (where do I find a "professional"? Remember, I live in Phoenix, Illegal alien capital of the world!)
I explained to him that I had NO confidence in Home Depot being able to adjust my "non-adjustable" carb and he understood.
(And a BIG thanks to some idiot lawmaker in California for demanding that my carb NOT run correctly if shipped to a different altitude than where it was originally set!)
I then asked him if there was anything of interest down inside the hollow throttle shaft as I seemed to remember someone saying that the high speed mix screw was hiding down there. He said that he could neither confirm nor deny that there was anything down inside the throttle shaft but that I could look again a little closer to see for myself! LOL
The answer is......YES, there is a high speed mix screw down inside the throttle shaft. The shaft may or may not be plugged with a small brass plug. Either way, it takes a very tiny screwdriver to access this screw and one CAN make adjustments on this carb. So with all that said, I can neither confirm nor deny that my trimmer has been re-adjusted to a much better mixture resulting in a cleaner burning, less poluting running quality, but my grass did NOT stand a chance this morning and I was done in about half the usual time!!!

Mark

 

[1977c10phxdriver]

Here is picture of the carb and the mix screw down inside the throttle shaft.

 

[Craig in Canada]

As the original poster of my SRM-210 woes here

Thank you
Thank you
Thank you

I'm know what I'm taking apart this weekend

Craig.

 

[1977c10phxdriver]

Craig.....Hope you get yours straightened out.

No matter how (stupid) sneeky the manufactureres are, we are bound and determined to find a way around the "improvements"! LOL