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View Full Version : I run my trimmers half throttle


tacoma200
06-15-2011, 05:33 PM
I know you are supposed to run trimmers wide open throttle (wot) but I find much of the time I'm working around delicate plants, close to auto's, rocky ground, etc and rarely do I have the trimmer at full throttle unless I'm in open area's. If the trimmer doesn't last as long then that will just have to be the case. One of the reasons I like the 4 mix is the low end torque. Many small trees and plants have no protector around them and I sure can't see running the trimmer at high rpm's and not nicking the bark. I have only lost one trimmer in the last 10 years. I wore a Stihl 80 completely out after many seasons. So regardless of how they are designed I will keep using them at low rpm in many places.

RECESSION PROOF MOWING
06-15-2011, 05:38 PM
I know you are supposed to run trimmers wide open throttle (wot) but I find much of the time I'm working around delicate plants, close to auto's, rocky ground, etc and rarely do I have the trimmer at full throttle unless I'm in open area's. If the trimmer doesn't last as long then that will just have to be the case. One of the reasons I like the 4 mix is the low end torque. Many small trees and plants have no protector around them and I sure can't see running the trimmer at high rpm's and not nicking the bark. I have only lost one trimmer in the last 10 years. I wore a Stihl 80 completely out after many seasons. So regardless of how they are designed I will keep using them at low rpm in many places.


And have great results and control doing just that. Trimmers last for years with no harm. There is no need to wrap out a trimmer for basic residential or even light duty commercial jobs. I can mow a church or business or home lawn on half throttle and put down beautiful lines just as easily as full bore throttle.

Ridin' Green
06-15-2011, 05:45 PM
I guess I must be a dumb arse, because I didn't know you were "supposed" to run them at WOT all the time. I only do if the operation calls for it. I barely have to run the FS 90 R more than idle for most apps.
My old Ryobi 4 stroke still runs good (needs a new primer bulb right now), and I have always run it only as fast as needed to do the job. It's in its 11th year now, and has been used for some serious work, and run often. I have never even adjusted the valves in it yet.
I guess I'll have to see what happens with the FS now. If I had never found this out, it would have went 20 years, but now that I know this, I'll probably only get 3 :rolleyes:

G. Ramey
06-15-2011, 05:54 PM
I have run mine half throttle for years and I believe they last longer. I know for sure I save fuel. I cut a couple of cemetarys and I run the trimmer at half throttle because of the gravel on the graves. My helper runs his wideopen and then complains about the bloody wounds on his legs from the gravel hitting him.

ed2hess
06-15-2011, 06:30 PM
I don't understand the statement that a valve machine has good low end torque? I have 4 of the Shindawa 2510 and low end torque is the problem. You can't edge with a unit that accelerates slow at low rpm. And it is easy to tune in a two stroke at low rpm...especially those with high torque heads. Anyway......we never run a unit anywhere near top rpm unless we are clearing some weed patch.

tacoma200
06-15-2011, 06:34 PM
I have been told by Stihl and other dealers they are designed to be used wide open throttle. I have been told not to lug them. This was before 4 mix engines though. Not sure if they still recommend this or if the dealers didn't know what they were talking about.
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Ridin' Green
06-15-2011, 06:36 PM
4 stroke engines have always been known for their low end torque. The big 4 stroke dirt bikes will run along a trail at just above idle in almost any gear because of the low end torque, while a 2 stroke needs to be wound up to the powerband to pulll along in a higher gear.

It holds true for any 4 stroke engine. It doesn't mean that 2 strokes can't or don't turn up equal torque, but they need to be running at much higher rpm's to do it.

tacoma200
06-15-2011, 06:41 PM
I don't understand the statement that a valve machine has good low end torque? I have 4 of the Shindawa 2510 and low end torque is the problem. You can't edge with a unit that accelerates slow at low rpm. And it is easy to tune in a two stroke at low rpm...especially those with high torque heads. Anyway......we never run a unit anywhere near top rpm unless we are clearing some weed patch.

I just know the 4mix units I own run stronger at low rpm's and the 2 strokes seem to have the power at higher rpm's . I know even though I wasn't an early 4mix convert it is now the first trimmer someone will grab.
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soloscaperman
06-15-2011, 07:32 PM
Anyone who runs it WOT is an idiot. All my life I have ran 1/2 throttle or even 1/4 throttle and never had a problem on my trimmers. I even run my mixture a little heavy with Echo oil and never had a spark plug go bad or exhaust screen clog.

weeze
06-15-2011, 07:36 PM
i think it's the 2 strokes that you have to run at higher rpms since they don't have as much torque.....that's one reason i like 4 strokes....you can save alot of gas and you don't have to rev it all the way to have the power to cut through stuff....it's really helpful around beds and such so you don't throw mulch everywhere...i rarely ever run mine at full throttle...maybe it it's like 3 ft tall weeds or something and really thick lol...i probably run it at 1/2-3/4 throttle on average...a 2 stroke on the other hand doesn't even cut anything until you get it to 3/4 throttle or higher lol.

93Chevy
06-15-2011, 07:38 PM
I use as little throttle as possible...saves on trips back to the truck to fuel up.

soloscaperman
06-15-2011, 07:40 PM
I use as little throttle as possible...saves on trips back to the truck to fuel up.

Also saves not just fuel but string.

soloscaperman
06-15-2011, 07:42 PM
i think it's the 2 strokes that you have to run at higher rpms since they don't have as much torque.....that's one reason i like 4 strokes....you can save alot of gas and you don't have to rev it all the way to have the power to cut through stuff....it's really helpful around beds and such so you don't throw mulch everywhere...i rarely ever run mine at full throttle...maybe it it's like 3 ft tall weeds or something and really thick lol...i probably run it at 1/2-3/4 throttle on average...a 2 stroke on the other hand doesn't even cut anything until you get it to 3/4 throttle or higher lol.

Sounds like about time to buy a Husqvarna trimmer then ;-)

93Chevy
06-15-2011, 07:42 PM
Also saves not just fuel but string.

That's true, but I don't care about string...I always keep extra in my pocket. Don't have to go back to the truck for that.

weeze
06-15-2011, 07:46 PM
Sounds like about time to buy a Husqvarna trimmer then ;-)

that's all i used before i bought my honda...they both are good but you have to rev up the husqvarnas more since they are 2 stroke...the honda will cut stuff at idle almost lol...i can go all day without having to put more gas in it which is pretty cool.

nolanjim
06-15-2011, 08:16 PM
I've mostly done half throttle on my 2 strokes and no problems my trimmers last a long time.
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Alan0354
06-16-2011, 04:22 AM
It is not convenient to trim at wot, things flying all over the place. Hedge trimming too, it is much harder to control if you have it wot.

topsites
06-16-2011, 09:27 AM
Put in 5, 10 years and this story just repeats itself.

All of it, the stuff with the torque, the stuff about the old machines but maybe not the new, all of it.

Ridin' Green
06-16-2011, 01:23 PM
Put in 5, 10 years and this story just repeats itself.

All of it, the stuff with the torque, the stuff about the old machines but maybe not the new, all of it.

So what?


If it helps newer and younger guys do the right thing or learn something, then it's still useful.

ALC-GregH
06-16-2011, 03:36 PM
I have been told by Stihl and other dealers they are designed to be used wide open throttle. I have been told not to lug them. This was before 4 mix engines though. Not sure if they still recommend this or if the dealers didn't know what they were talking about.
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What it amounts to is, most all 2 cycle engines are made to run at a higher rpm to reach the maximum torque then a 4 cycle. Obviously 4 cycles have more low end torque.

Nice thread too by the way.

I have a Echo 210 with speed feed head and a Edgit. It turned 14 this year. It's always had Amsoil mixed at 80:1 and has never seen a shop until a few days ago when it lost power. I don't have the time to mess with it. The dealer is cheap and knows what to do. Normally I'd mess with it and fix it. It shouldn't cost much and I'm sure it will go a few more years.
I never run more then 1/2 throttle unless I need more as long as it's away from anything that could be damaged from flying debris. If I need more power, I have a FS90R that knocks down heavy growth with way less effort.

jsslawncare
06-16-2011, 04:03 PM
I never run my at wot either. They have enough power at half thottle and don't use as much fuel.

Will P.C.
06-16-2011, 07:26 PM
Does anyone have any actual evidence about running at 1/2 is bad for the machine?

I remember reading one thread on here about trimming w/o the guard and the majority of guys claimed running at 1/2 was bad for the machine

Personally, I almost always run at 1/2 throttle. I think running at WOT puts stress on the engine.

Tofutti
06-16-2011, 07:43 PM
If I had to guess, I would think that maybe the only thing that might be more prone to injury when running the machine at lower RPM would be the shaft.
At least a flex shaft anyway..

When you come into something a little heavier and you're a little too slow on the line speed, you notice how the head kind-of torques around a bit until you rev it enough to make the cut. I'm guessing the engine could probably care less, but that shaft and maybe the clutch has to take that energy. Something does.
..Similar to having too much line out.. the machine sort-of jumps and quivers while coming up to speed.

By the way, I also am a strong advocate of running just enough RPM to make the cut. Actually have one machine's idle screw set up enough above idle to keep the clutch engaged plus a little bit for throttle-free trimming lol.

freshprince94
06-16-2011, 08:33 PM
I run at the throttle that the job needs. Most of the time it's about 1/2-3/4, rarely WOT. I only WOT it if i'm doing an open area or if I have a lot of overgrowth. That's with the trimmer. I only run my edger at WOT because it leaves a crappy edge and takes too long if you go any slower.

GlynnC
06-16-2011, 08:52 PM
I've always heard that 2-strokes were more likely to carbon up the exhaust if run at less than wot. In the past few years I've repaired equip part time and mowed part time. One of my guys for equip repairs runs 2 crews full time, usually 2 men per crew running trimmers/blowers. He claims they run at wot, with the line longer than I would ever think of running. His trimmers carboned up much more than my other customers. I think it was more from running the trimmers under heavy load.

I run the same trimmer as this guy (Kaw KGT27A) at only the speed to get the job done, and have not had a carbon issue--but I'm not running the hours either.

ed2hess
06-16-2011, 09:22 PM
[QUOTE=ALC-GregH;4065487]What it amounts to is, most all 2 cycle engines are made to run at a higher rpm to reach the maximum torque then a 4 cycle. Obviously 4 cycles have more low end torque.

Nice thread too by the way.
QUOTE]

I am still not buying that high torque thing on 4-mix I got both and hands down the echo 2 stroke can run at just about any rpm you want and does a fine job. I know that if I gun a 2 stroke it gets to max rpm faster than the 4 mix. I also know that if I try to edge with the 4mix at lower rpm the unit oscillates up and down. Now I havent run the stihl 4 mix it might be different.

ashgrove landscaping
06-16-2011, 09:46 PM
Run them how ever you like and what works for the job. There is no supposed to in this line of work. Hahaha.. There's times where I just burp it along and others it half and full.

Ridin' Green
06-16-2011, 10:15 PM
[QUOTE=ALC-GregH;4065487]What it amounts to is, most all 2 cycle engines are made to run at a higher rpm to reach the maximum torque then a 4 cycle. Obviously 4 cycles have more low end torque.

Nice thread too by the way.
QUOTE]

I am still not buying that high torque thing on 4-mix I got both and hands down the echo 2 stroke can run at just about any rpm you want and does a fine job. I know that if I gun a 2 stroke it gets to max rpm faster than the 4 mix. I also know that if I try to edge with the 4mix at lower rpm the unit oscillates up and down. Now I havent run the stihl 4 mix it might be different.

When you refer to 4 mix, are you referring to 4 strokes in general? I ask because in this quote of your post you say you haven't run a Stihl towards the end of it, so I'm wondering which 4 stroke you are talking about. While a 4 stroke Ryobi, CC, or Honda etc., home owner trimmer works fine, they're no comparison to the Stihl 4 Mix commercial trimmers.

2 strokes do rev quicker sine they fire every other stroke, while the 4 strokes fire every four, so half as often.
However, if you run a 2 stroke at low rpm's with much of a load on it (I'm not talking light/normal grass around a tree or something like that), it'll either bog right down, the clutch will slip, or the engine will die. It takes far more to do it toa decent 4 stroke at low idle.


I have both types, and both do the job fine under normal conditions, but a decent 4 stroke will out muscle a 2 stroke at low revs every time.

walker/redmax
06-16-2011, 11:27 PM
L.I.A - lets invent acronyms!... and I'll second the notion that anyone that runs at "wot" is an idiot. A.T.R.W.O.T.I.A.I if you will...

Sammy
06-17-2011, 07:30 AM
As many r.p.m.'s as needed to get the job done.
If it be 1/4, 1/2, 3/4 or full.

Sammy
06-17-2011, 07:31 AM
Have a friend that cut his mail box post in half with his trimmer ! ..... LOL

Sammy
06-17-2011, 07:32 AM
L.I.A - lets invent acronyms!...

Lets not, and say we did.

GlynnC
06-17-2011, 09:31 AM
[QUOTE=Ridin' Green;4066037][QUOTE=ed2hess;4065925]


2 strokes do rev quicker sine they fire every other stroke, while the 4 strokes fire every four, so half as often.

Not that anyone really needs to know (or cares), but a 2-stroke fires every time the piston comes to the top, and a 4-stroke fires every other time. The downward movement is considered part of the stroke as well.

On the upward movement of the piston, a 2-stroke pulls in fresh fuel/air into the cylinder, and at the same time, pushes out the burned fuel/air (from the previous firing) thru the exhaust. This is why it's a "dirty engine"--a small amount of the fresh fuel mix merges with the exhaust and is pushed out also. As the piston moves up, the fuel mixture is compressed, there is ignition firing, and the piston is pushed down. The downward movement of the piston compresses fuel mix in the crankcase area, and this pushes new fuel into the cylinder at the appropriate time--then the process starts over.

On a 4-stroke, on the compression stoke, fuel/air mixture is already in the cylinder, both valves are closed, the fuel is compressed as the piston moves up, and at approximately the top of the movement, there is ignition firing and the piston is pushed down; as it comes back up, the exhaust valve is opened, and the burned mix is pushed out the exhaust. The exhaust valve closes, the intake valve opens and new fuel mix is pulled into the cylinder as the piston goes down the second time.

Whew----this all makes me tired just thinking about all that happens inside these little tiny engines!!!!!!!!!!!!!!!

Ridin' Green
06-17-2011, 11:27 AM
[QUOTE=Ridin' Green;4066037][QUOTE=ed2hess;4065925]


2 strokes do rev quicker sine they fire every other stroke, while the 4 strokes fire every four, so half as often.

Not that anyone really needs to know (or cares), but a 2-stroke fires every time the piston comes to the top, and a 4-stroke fires every other time. The downward movement is considered part of the stroke as well.

On the upward movement of the piston, a 2-stroke pulls in fresh fuel/air into the cylinder, and at the same time, pushes out the burned fuel/air (from the previous firing) thru the exhaust. This is why it's a "dirty engine"--a small amount of the fresh fuel mix merges with the exhaust and is pushed out also. As the piston moves up, the fuel mixture is compressed, there is ignition firing, and the piston is pushed down. The downward movement of the piston compresses fuel mix in the crankcase area, and this pushes new fuel into the cylinder at the appropriate time--then the process starts over.

On a 4-stroke, on the compression stoke, fuel/air mixture is already in the cylinder, both valves are closed, the fuel is compressed as the piston moves up, and at approximately the top of the movement, there is ignition firing and the piston is pushed down; as it comes back up, the exhaust valve is opened, and the burned mix is pushed out the exhaust. The exhaust valve closes, the intake valve opens and new fuel mix is pulled into the cylinder as the piston goes down the second time.

Whew----this all makes me tired just thinking about all that happens inside these little tiny engines!!!!!!!!!!!!!!!

You are of course correct.

I shouldn't type when it's that late at night I guess.:o Thanks for correcting me. Details are important as far as I'm concerned.:)

Ridin' Green
06-17-2011, 11:43 AM
I just wanted to ad that technically I was correct in my post above that you quoted, but it could have been misleading to someone who didn't know the sequence of events inside an engine, so again, thanks for the clarification.

GlynnC
06-17-2011, 01:49 PM
I just wanted to ad that technically I was correct in my post above that you quoted, but it could have been misleading to someone who didn't know the sequence of events inside an engine, so again, thanks for the clarification.

Just for the record, I didn't read yours as being incorrect--it wasn't. I thought I'd just explain a little more. The mechanical process of equipment is of great interest to me, and always makes me think that I'm proud there have been smarter people in the world than me--we'd still be trying to invent a round wheel if it had been up to me.

Ridin' Green
06-17-2011, 01:56 PM
I'm proud there have been smarter people in the world than me--we'd still be trying to invent a round wheel if it had been up to me.

Same here bro!:)

billythekid
06-17-2011, 04:50 PM
i don't run my mower or my trimmer at WOT. I ride dirt bikes and yes i agree with the comment on that and you'll also learn that 2 strokes need to be opened up every now and then to clear them out.

4 stroke trimmers seems like a good idea until you have to change oil in them.

SouthSide Cutter
06-17-2011, 05:23 PM
I know this is gonna sound like BS but here goes. I think my 4mixes use more gas than my 2 strokes. I run my FS100RX's at what throttle they need. But they seem to run better wide open. Mowed a pond dam the other day and thought I would have to fill up a couple times before I got done. Just judging the size of the job to every day running. Well it didnt use hardly any gas which shocked me. And I run it wide open the whole time.

tacoma200
06-17-2011, 07:18 PM
I know this is gonna sound like BS but here goes. I think my 4mixes use more gas than my 2 strokes. I run my FS100RX's at what throttle they need. But they seem to run better wide open. Mowed a pond dam the other day and thought I would have to fill up a couple times before I got done. Just judging the size of the job to every day running. Well it didnt use hardly any gas which shocked me. And I run it wide open the whole time.

My 4mixes us less? :confused:

Ridin' Green
06-17-2011, 11:04 PM
i don't run my mower or my trimmer at WOT. I ride dirt bikes and yes i agree with the comment on that and you'll also learn that 2 strokes need to be opened up every now and then to clear them out.

4 stroke trimmers seems like a good idea until you have to change oil in them.

The 4 mix type trimmers like those from Stihl, don't have an oil tank. That's what makes them 4 "mix". They run on 2 stroke gas/oil fuel, but are actually a 4 stroke with valves and all.