tobster
ArboristSite Lurker
Does it damage a two-stroke engine to run it a less than full throttle? Some claim the engine doesn't get proper lubrication. I remember reading something to that effect but a search didn't turn up any results.
i
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half-throttle
- Thread starter tobster
- Start date
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Gypo Logger
Timber Baron
Apparently not, unless the saw gets a steady diet of it.
Log home builders could answer that alot better than I.
They are constantly using 1/2 throttle when making saddle notches etc., but WOT when making bucking cuts.
This type of operation may call for 50:1.
John
Log home builders could answer that alot better than I.
They are constantly using 1/2 throttle when making saddle notches etc., but WOT when making bucking cuts.
This type of operation may call for 50:1.
John
Zombiechopper
Addicted to ArboristSite
My understanding is that the small carbs on modern saws do not deliver fuel evenly across the full rpm range. They meter fuel properly at full rpm and may or may not at part throttle. So they could be running lean at part throttle and not at full throttle
Back in 2006 member stihltech told me that almost all the newer Stihl saws had a midrange jet. He said that's why the 029 high side needed to be tuned in the wood.
o8f150
Tree Freak
now this is what i have always heard.. that it is better and easier on the 2 stroker to run it wot
The incoming charge of fuel and air cools the engine, especially the piston and at full throttle it gets the maximum amount, at lower speeds its hit or miss with the amount of fuel flowing into the airstream so there are spots below WOT that the engine would be running lean and getting less than optium cooling.
Pioneerguy600
Pioneerguy600
The real lube problem is when you coast in gear with a 2 stroke vehicle. (not enough fuel/oil with the throttle at idle to lube the engine at high RPM)
That's why the old 3 cylinder Saabs had a freewheel in the transmission, so that when you lifted the throttle the engine dropped to idle RPM.
That's why the old 3 cylinder Saabs had a freewheel in the transmission, so that when you lifted the throttle the engine dropped to idle RPM.
Zombiechopper
Addicted to ArboristSite
makes sense. Don't downshift a 2 smoker!
It can't be too much of a problem or the manufacturers wouldn't put a trigger on chainsaws..they'd fix the carburetor in wide open mode or leave the butterfly out of the carburetor!
CGC4200
Addicted to ArboristSite
Warming up @ 1/2 throttle
The last several years I got into the habit of starting a cold saw,
then letting it sit running for 20 seconds or so to let engine warm and
chain oiler get to pumping. I don't do this with anyone else nearby.
I don't hesitate to feather throttle near end of a cut or when otherwise
needed, but anytime else, it is full throttle.
The last several years I got into the habit of starting a cold saw,
then letting it sit running for 20 seconds or so to let engine warm and
chain oiler get to pumping. I don't do this with anyone else nearby.
I don't hesitate to feather throttle near end of a cut or when otherwise
needed, but anytime else, it is full throttle.
T_F_E
ArboristSite Operative
The the majority of saws are jetted high and low so that where it should be ran, high and low.
SawTroll
Information Collector
I believe that is true.....
I have never seen proof of a single exception - but they could still exist!
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B_Turner
Addicted to ArboristSite
You wouldn't want to make long cuts (felling or bucking) partial throttle, IMO. Particulary longish cuts with much of a load on the saw. Why would you want to, anyway?
But I don't think a little partial throttle hurts most saws. All my saws get some partial throttle, some more than others.
But I don't think a little partial throttle hurts most saws. All my saws get some partial throttle, some more than others.
SawTroll
Information Collector
Why would Stihl put an adjustable throttle lock on the BG85 blower if it wasn't designed to be used at any speed other than idle or wide open? I've used it at ½ throttle for blowing leaves, the garage floor & the sidewalk for 8 years now when full power isn't needed. I haven't experienced any problems whatsoever with it. Must be that damned Amsoil @ 70:1 ratio I've been using. 
THALL10326
The Champ
Half throttle actually causes most two cycle engines not to fully burn what fuel it gets at half throttle leading to clogged muffler screens and exhaust ports. Half throttle on a chainsaw causes the clutch to overheat because its not fully engaged at half throttle causing it to slip againist the drum while under a load...
E.V.A. Sawman
ArboristSite Operative
As a builder of 2-stroke snowmobile race engines, which are equipped with a low speed idle adjustable jet, a low or mid range jet, and a high speed or main jet this allows the constant flow of fuel so there is no hot spots in the operation range. The fuel cools the engine, that is why a racer that comes into a corner from a long straight will blip the throttle, to keep his engine cool and lubricated, a liquid cooled 2-stroke operates on tighter specs and is more prone to temperature seize. liquid cooled engines need to warm up to operating temp. otherwise if they are run hard right after initial start up, expansion in the piston will cause whats known as cold seize. Air cooled 2-strokes are more forgiving. half throttle may keep it cool if the saw is not worked hard but the carb on a saw is designed for best operation at idle and wot. They only have the 2 mixture controls.
B_Turner
Addicted to ArboristSite
Maybe not a little, but carving is a well known chainsaw killer......opcorn:
If you saw how badly many carvers maintain their saws you would 1) be horrified and 2) understand why some of them go through saws.
Other carvers get many many hours out of their saws.
But I agre too much partial throttle is looking for trouble.
MS460WOODCHUCK
Addicted to ArboristSite
Why would'nt you run a saw WOT in most conditions?:monkey:
SkippyKtm
The Lorax, my FIL rip...
I run my 51 plenty at part throttle, Its my primary saw I use for roughing out joints on the timber frame I'm building. I bought it new back in '93 -been putzing around on that frame for nearly ten years now, and the saw hasn't died yet, I'll let ya know if it does.. (but I doubt it!
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