Chainsaws at 10,000 ft

[8150 Steve]

I recently bought 10 acres in SW Colorado at 10,000ft elevation and have a ton of trees to clear before we starting building a cabin. Most of the trees are 6-20" so I picked up a Stihl 261cm 16" and a 500i with a 25" bar. Both start and run great at 7,000 ft but struggled this weekend which was my first time using them at 10k. The 261cm started right up but would not re-start after running through a first tank of gas.

The 500i took me an hour to get started then ran great but would not start at all on day 2. I pulled the plug and cleared the combustion chamber half a dozen times. It would sound closer to starting after clearing it but never dig get it to fire up today. Got home to 7k tonight and both fired up within 3 pulls.

Any thoughts on either saw at 10k or do I need to look for something different?

 

[osadayo99]

Good evening Steve, A lot of the work we do is 8000-11000 ft. Most of the crews that have the Stihl M-tronic {chip} or the Husky auto-tune saws have problems with them at these higher altitudes.
I can't really address with first hand knowledge regarding Stihl saws but The Huskys take some finessing until warmed up. We solved most of the high altitude starting and re-starting problems by letting the saw run on high idle for a bit then hitting the throttle once and let them warm up before regular use. Seems to work for the guys using MS362Cs as well as those of us running 562XPs
Most of our problems seemed to have come from using the saws right after initial fire-up
Never had this kind of problems at high altitude with our 372XPs or MS 440s (adjustable carb tuning}


hope this might help !

 

[Ted Jenkins]

My experience at higher altitude dictates that the auto tune is not for me. I set up a few manual tune saws with some modifications. It feels like I get about 85% performance at 10,000. Once tuned they can not be used at 4,000 or 5,000 feet and below. Actually I have only run a couple at 7,000 feet. There are several threads here that deal with that. Thanks

 

[8150 Steve]

Thanks Osadayo99 - appreciate the info. I am leaning toward picking up an adjustable carb husky while also trying to get the sthil saws figured out.

 

[ValleyForge]

I recently bought 10 acres in SW Colorado at 10,000ft elevation and have a ton of trees to clear before we starting building a cabin. Most of the trees are 6-20" so I picked up a Stihl 261cm 16" and a 500i with a 25" bar. Both start and run great at 7,000 ft but struggled this weekend which was my first time using them at 10k. The 261cm started right up but would not re-start after running through a first tank of gas.

The 500i took me an hour to get started then ran great but would not start at all on day 2. I pulled the plug and cleared the combustion chamber half a dozen times. It would sound closer to starting after clearing it but never dig get it to fire up today. Got home to 7k tonight and both fired up within 3 pulls.

Any thoughts on either saw at 10k or do I need to look for something different?

Did you Try resetting the 261? It learns on its own but it may be struggling adjusting to the atmospheric pressure since it’s an odd parameter that usually doesn’t change during normal saw operation.

I'm not sure you can reset the 500 but I would assume the saw is having trouble being short on pressure when you pump up the injection side of the system. i would think you’d have to pump it up more than the minimum 8 times recommended to account for the lower pressure.

just some thoughts….

 

[8150 Steve]

Did you Try resetting the 261? It learns on its own but it may be struggling adjusting to the atmospheric pressure since it’s an odd parameter that usually doesn’t change during normal saw operation.

I'm not sure you can reset the 500 but I would assume the saw is having trouble being short on pressure when you pump up the injection side of the system. i would think you’d have to pump it up more than the minimum 8 times recommended to account for the lower pressure.

just some thoughts….

I reset the 261 out of the gate but will reset it again next time I am up there. The 500 is still a puzzle. I tried pumping anywhere from 6-12 times with no luck. I may also try running both through a few tanks at 7k to see if a little break in helps out.

 

[8150 Steve]

My experience at higher altitude dictates that the auto tune is not for me. I set up a few manual tune saws with some modifications. It feels like I get about 85% performance at 10,000. Once tuned they can not be used at 4,000 or 5,000 feet and below. Actually I have only run a couple at 7,000 feet. There are several threads here that deal with that. Thanks

Starting to lean that way as well. I will likely set up a couple manual tune saws that I will only use around the land. Currently thinking about trying a Husky 455 or 460 and a 372. Anyone have other recommendations for manual tune saws for 10,000 ft?

 

[ValleyForge]

I reset the 261 out of the gate but will reset it again next time I am up there. The 500 is still a puzzle. I tried pumping anywhere from 6-12 times with no luck. I may also try running both through a few tanks at 7k to see if a little break in helps out.

If I recall the fuel schematic correctly on the 500, you can’t over pressurize it since it has a relief on the high pressure side. The bulb is not a primer like on other equipment, it is there to pressurize the injector to allow it to start. Keep trying until you find out what works.

Also, what gas are you using? high octane doesn’t work well at high altitudes since it volatizes easier, that’s why you can’t get 93 at the pump in Denver like we can here on the Eastern Shore.

 

[3000 FPS]

One other thing to consider when taking a saw from 5000 to 10,000ft is the compression. You can lose a bunch of compression at those high altitudes. Enough to notice less performance. So If you feel like you are only getting 85% performance then that is to be expected.

 

[8150 Steve]

If I recall the fuel schematic correctly on the 500, you can’t over pressurize it since it has a relief on the high pressure side. The bulb is not a primer like on other equipment, it is there to pressurize the injector to allow it to start. Keep trying until you find out what works.

Also, what gas are you using? high octane doesn’t work well at high altitudes since it volatizes easier, that’s why you can’t get 93 at the pump in Denver like we can here on the Eastern Shore.

Good info. I used stihl moto mix this weekend which is 93 octane. Anyone else run lower octane at elevation? I will definitely try it.

 

[Mad Professor]

If I recall the fuel schematic correctly on the 500, you can’t over pressurize it since it has a relief on the high pressure side. The bulb is not a primer like on other equipment, it is there to pressurize the injector to allow it to start. Keep trying until you find out what works.

Also, what gas are you using? high octane doesn’t work well at high altitudes since it volatizes easier, that’s why you can’t get 93 at the pump in Denver like we can here on the Eastern Shore.

High octane is less volatile.

 

[Mad Professor]

Starting to lean that way as well. I will likely set up a couple manual tune saws that I will only use around the land. Currently thinking about trying a Husky 455 or 460 and a 372. Anyone have other recommendations for manual tune saws for 10,000 ft?

Pre-limiter cap Stihls. 026 036 038M 044 064

 

[ValleyForge]

High octane is less volatile.

Indeed prof, my thought was it becomes more volatile at altitude but not enough to counter the thin air. I should have typed that better.

 

[ValleyForge]

Pre-limiter cap Stihls. 026 036 038M 044 064

I heard from my stihl dealer when I went to pick up my new normal 261 that they are going to do away with limiters since California no longer allows gas saws….anyone else hear that?

 

[FunkyYota]

I live at 9000, routinely cut at 10+. My 261cm works fine. Mine kinda ran like crap for the first 5 tanks or so.

That said my other saws all have screws and it’s kinda nice to be able to adjust it and know where things are.

On my 460 I put in a pop up piston and advanced the ignition timing a bit which helped recover some lost power.

 

[oldbuzzard]

I live in northern CO and occasionally cut at 9000’ plus. I have both 261CM and Husky 550XP and don’t have too many problems but they can be touchy when you make big altitude/temp changes. One cardinal rule I have learned is to FIRST try starting them WITHOUT the choke. Then when you get it started just let the saw idle for a minute on fast idle, then regular idle. I take the chain brake off while it is idling and you can see the chain rpm changing up and down while it “tunes” itself. Watching the chain is a lot better than listening for the saw to tune itself.

 

[Cliff R]

I've been hunting in Colorado for many years and zero issues with any of the saws we've taken along to cut firewood, other than they are down on power from what they are here at 1200'. We camp at 9600' and cut as high as 12,000' but most is done closer to camp about 9600-10k..

Slight re-tuning is required. Before I even fire one up I'll increase the idle speed screw 1/2 to 3/4 turns, start as I would here, then trim the "L" speed screw in a bit to get it to idle at it's best. Once it's idled a minute or two I'll make a cut and tune the "H" speed screw for best power in the cut.

Not much more difficult than that. That procedure works for every saw I've taken with us over the years. I like to take one of my Husqvarna 55's (closed port) as they have high compression and don't fall off as much as some of the others. I've taken the Echo CS-370 a few times, it starts and runs well but WAY down on power and slow in the cut.

I'll add here that we also take our older Honda 500 Quads and they have carburetors. They are flawless at any altitude. The only adjustment required for them is to turn the idle speed screw in about a full turn and very little use of the enrichener is needed to get them going on a cold start. I also switch over to Colorado's "low" octane fuel when we drop out of Wyoming and drop in from the North. Made the mistake once of leaving some 93 octane in one of the saws we took along and it didn't work well at all till we dumped it out and re-filled with 85 octane (pretty sure that's what we get out there).

So aside from going to lower octane fuel and a slight re-tune zero issues now for well over 20 years on our out West hunting trips.........

 

[osadayo99]

Steve, as far as looking into buying a Husky , Ya can't go wrong with " the workhorse" 372XP . Our crews use them and the MS440-460 up high in bigger timber.

*had this original 371xp since new , put a new 372XP OEM cylinder/piston kit along with new crank , seals and bearings . usually run a 24" bar, sometimes a 28" Always holds it's own
Happy Shopping !!!

 

[snobdds]

I have a cabin at 10k feet where I have cut hundreds of pine beatle kill trees over the past 10 years. I use a tack to set my saws up. I tune them at my house at 6500 to run a little lean, usually by 500 rpms. When I take them up to elevation, they usually hit the sweet spot.

So in my experience, the difference between the tuning at 6500 and 10k is about 500 rpms.

Hope that helps.

 

[8150 Steve]

Steve, as far as looking into buying a Husky , Ya can't go wrong with " the workhorse" 372XP . Our crews use them and the MS440-460 up high in bigger timber.

*had this original 371xp since new , put a new 372XP OEM cylinder/piston kit along with new crank , seals and bearings . usually run a 24" bar, sometimes a 28" Always holds it's own
Happy Shopping !!!

Just got an 372xp on order. Our local Husky dealer/mechanic is pretty solid so decided to give him some business. Will probably pick up a smaller husky as well (450 or 455). Anyone recs on that???

I think the 261 likely overheated. Still playing with the 500i while I wait on a local guy to look at it.