Coldish weather saw operation

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Burnham

Burnham

Woods walker
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Mar 7, 2005
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I've been doing some thinning and pruning around our place this fall and early winter, and I was reminded of the recommendation in the Stihl operator's manuals for my several saws that we need to adjust the carb pre-heat shutter for colder air temps.

The funny thing is, they call for it at what seem like very mild temps to me, like under 50 degrees F. So heads up kids, check it out for your saws.

I wasn't noticing any issues operating in the 30's, but decided to change the shutters anyway. Ran the 361 for a day in the upper 20's before changing the shutter, too. Still seems like fairly mild temps, but I dunno.

Be interesting to hear what some of you cold zone guys have experienced with this.
 
I think my Husky 66 has a plug in the front of the cover, maybe I should pull it and see what hapens. It's back above 0 F, now.
 
Like Jay says cold temps will make a saw run leaner, adjustments have to be made.
But the main reason for pre-heating the carb is preventing icing up conditions in the carbs venturi which will partially or completely cover over a port or nozzle. I've seen saws ice up in the PNW at high altitudes above freezing temps.
Always respect the info from your saws owners manual.
 
If I understand the function of these screens, they are used to siphon heat off the cylinder to warm the carb and prevent ice formation. Is this correct?
 
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  • #8
That's my understanding...which is why 50 degrees F. seems warmer than I'd expect the need for the shutter to be opened.

My manuals make no mention of elevation as a factor, Willard. Just temp. But of course you are correct, if the manual says so, why quibble...it's not hard to do. My manuals also say to close the shutters above 70 degrees F. or heat damage may occur. So 50 to 70 is ok either way, I guess.
 
I can tell if a saw is running or not. I can judge if its running good/bad sharp/dull but thats about it. Forget about diagnosing and fixing! I am good at getting them started though, as long as it works :)
 
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A lean saw will be hitting higher revs than normal, Nick. It's an ear thing to pick up on it, I think. So if it's not a saw you run regularly, I'd say it's a difficult thing to sense.

Visual spark plug electrode inspection will clue you in, of course.
 
Warm them up and slap on the digital tach if you're getting old like me and your high range hearing is going... huh? What'd ya say?
I don't know if technically it makes any sense, but we'd add a little oil to our mix in the extreme cold so the saw would get lubrication even if it was running lean from the deep freeze.
 
Burnham, with the antique saws that you are runnng, it ain't much of a problem.
The new Scavenge engine types only really run well when warmed through, and I've noticed that turning the little screw that turns the flap to winter setting makes a difference.
Mostly in the beginning, though. Once the saw is warmed through, it runs fine w/o.
 
Burnham said:
My manuals make no mention of elevation as a factor, Willard. Just temp.
Click to expand...
Burnham, I'll fully explain. When I worked for Stihl Canada in 1989 I was doing warranty claims for 064s that had lean seizures in high altitudes in the PNW (B.C.) with snow and slightly above freezing temps. The fallers were running the saws without the supplied winter kits of rewind housing covers and rubber flangeg air filter housing covers.
With the snow freely injested by the saws even though the weather temps were above freezing the velocity of air mixed with snow through the carbs venturi was causing icing conditions resulting in the lean seizures. The high altitude carb settings were also factored in.
The remedy was leave the rubber flanged air filter housing cover on to prevent snow being drawn through the gap between the top covers for the snow season and leave the warm air window shutter open. Rewind housing cover only attached when at the manuals reommended temperature.l
 
My guess is that probably the easiest way to sense basically if a saw is running leaner, is if the chain is moving at idle when it wasn't before. Right down there at that setting where you are getting max idle revs without the chain ticking, is a pretty sensitive point to changes. It may not be the only reason, but a distinct possibility if you haven't changed your gas mix or touched the carb.. It may not be so noticeable at max revs with the sound and without a tach, unless you have a good ear for it.
 
FireFighterZero said:
Gawd, i know what you mean. It says our windchill is -50 right now.
I know the snowmobilers run a little alcohol in the real cold to prevent a jet from freezing, is that something a person could do in chainsaws?
Click to expand...
Trouble with gas line anti freeze is it puts more moisture in the fuel tank. I tried it in my saws years ago and found it didn't help .It can degrade the fuel/ oil mixture as well
As long as your cutting in snowy freezing conditions you have to keep the carb preheated and stop the intake of snow and cut down the intake of cold air..
Husqvarna and Stihl supply the required winter kits for free if your in a cold climate zone.
 
Is that the standard arctic kit on the Stihl you're referring to Willard. It's heated handles and carb as far as I know. Are there any other differences you're aware of?
 
squisher said:
Is that the standard arctic kit on the Stihl you're referring to Willard. It's heated handles and carb as far as I know. Are there any other differences you're aware of?
Click to expand...
Justin, yes make sure the Arctic package includes the heated carb along with the heated handles, older models may be only one of the other.
Husqvarna also offer heated carbs but like the Stihl a rewind housing cover is part of the winter kit.
Plus Husqvarna has a plate to block off the air injection to prevent snow injestion. I have owned heated carb saws but found the standard winter kit works just as good as the heated carb model if used by the book.
 
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  • #23
stig said:
Burnham, with the antique saws that you are runnng, it ain't much of a problem.
The new Scavenge engine types only really run well when warmed through, and I've noticed that turning the little screw that turns the flap to winter setting makes a difference.
Mostly in the beginning, though. Once the saw is warmed through, it runs fine w/o.
Click to expand...

Antique, eh? Takes one to know one, I suppose :P.

I like that 064, and a year or so back I picked up a sweet 044 just because I couldn't stand to not buy it when the opportunity fell into my lap. Both are awesome machines, antique or not. My small saws are no spring chickens, but hardly antiques :).

Well anywho, I wasn't seeing any operations problems, but thought since the manuals call for it, I'd change 'em over.
 
That mean you'll be posting some cutting pics, Burnham? I note the absence lately since you stopped keeping things in line at the FS. Miss seeing them.
 
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