I know when tuning a chain saw it is done with the chain on. Problem is, a string trimmer will not run with the string always at full length. At what length of string should a trimmer's high speed adjustment be made? Thanks for the help guys.
Tuning a String Trimmer
- Thread starter Pilsnaman
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I don't follow? your string trimmer wont run with the string at full length??? get a new one
Otherwise I would say tune it to the string length u usually cut with.
Good luck
Craig
cuttinscott
Addicted to ArboristSite
Its an Echo GT-1100 but my question is more general. When tuning a string trimmer should it be done with the string at full length? While you use a trimmer the line length will slowly decrease, causing increased RPMs. This is unlike a chainsaw where a properly lubricated chain (not really old) will always run with around the same amount of resistance. I just noticed while using my trimmer last weekend that as the line gets shorter the increase in RPM will change how much "four cycling" the engine did while not cutting at WOT. It makes sense that it would require a different air/fuel mix at a different RPM I just want to make sure it is tuned while running under the correct amount of load. Thanks again.
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I gots 1 of them green weedeaters.. 7-8 years old. It has always ran faster as the string gets shorter. Darn good trimmer, only thing added is new line. And wash the air filter out 1-2 twice a year.. same ole plug since i bought it
So I looked up a few of the Husky manuals and the one from my trimmer. It is interesting that Echo recommends the string be installed at full length, to the cut off knife, while the Husky says to not only have no string but no string head attached. While I am going to just go by the echo manual for my trimmer this discrepancy seems strange. I thought all of these little two cycles would be about the same in how to tune them.
XJWoody
ArboristSite Guru
FWIW when I juiced up my little Husky 123L, I set the max RPMs without any string hanging out, but with the trimmer head attached... that way it won't be screaming like a banshee when the line gets short.
I tend to keep my line bumped out to a useful length, but there 'aint no telling how Mrs Woody runs it when I'm not around.
so I erred toward the side of caution.
I tend to keep my line bumped out to a useful length, but there 'aint no telling how Mrs Woody runs it when I'm not around.
so I erred toward the side of caution.
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I believe I remember one of the more knowedgeable members here talking about trimmers and the fact that they are always under load. You will not be able to get it to four-stroke because the engine is already "in the cut". When a saw four strokes it is not under load. You need to set it with a tach and not worry about 4-stroking. The same rule applies to blowers.
PetrolHead
ArboristSite Operative
G'day.
2 different ways I use to tune a line trimmer (H) side.
First way in under full load & full throttle, ie: with full line length. I turn the H in until max rpm, then turn rich until a small drop in rpm is noted, say around 100 - 200 rpm.
Second way is no load (no line), full throttle. Same as with a saw out of the cut, I adjust H rich until 4 stroking is audible. I usually find that if I use the first method and then take the line off, the thing will 4 cycle anyway.
Always worked for me.
2 different ways I use to tune a line trimmer (H) side.
First way in under full load & full throttle, ie: with full line length. I turn the H in until max rpm, then turn rich until a small drop in rpm is noted, say around 100 - 200 rpm.
Second way is no load (no line), full throttle. Same as with a saw out of the cut, I adjust H rich until 4 stroking is audible. I usually find that if I use the first method and then take the line off, the thing will 4 cycle anyway.
Always worked for me.
Yeah, tuning the thing to four stroke with the string in didn't seem right. I guess the resistance of a chain on a chainsaw is probably pretty comparable to that of the shaft on a trimmer. Now a blower I think would require a tach. How much are tachs and where can you buy one?
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