Choosing a saw for high altitude

[Uglyhat]

Greetings - first post but I'd like to get right to the point.

I'm needing a good firewood saw for between about 7000 and 9500 feet in elevation. Years past I used a slightly modded 044 with a 30" bar and full chisel chain at lower elevations in Oregon - wish I still had that one but I don't. So I'm accustomed to a decent amount of cutting power.

The new saws have me rather confused, and now that I'm cutting wood again I'll get my chainsaw reeducation in due time, but I'm hoping for the voice(s) of experience to expedite my saw and firewood acquisition.

'been looking at the new Stihls - not terribly brand loyal but where I live the best shops service and sell Stihls. I'm told the EPA regs now have the adjustability limited and saws crippled, but don't know how true this is. Sales folk tell me they run fine at altitude and can still be adjusted 'a little bit'. Some Stihls have the 'Intellicarb' compensating thingamajig supposedly for altitude and filter clogging, but the "NEW!" Stihls say nothing about compensating carbs.

I have no problems buying an older saw which I can jet down and otherwise tinker with, but I don't know how far back parts are readily available for various models and brands. I can spend the $$ on a new saw, but would hate to learn after the fact I shoulda got an older hot rod saw.

Weight is somewhat of an issue; I'm thinking a 20" bar will be sufficient but the wife will get grumpy if she has to wait long for me cutting to carry wood back to the truck. I'm looking in the 272 to 362 range, at least as far as Stihls go.

Thanks heaps and awaiting your responses ...

 

[Bounty Hunter]

Hey Uglyhat,

Welcome to the ArboristSite Forum...Interesting username, where didya get that?

As for high altitude...that's my gig too, usually 6000 to 8000, and sadly you do feel a big difference in overall saw power...especially if you run (and re-tune) the same saws at much lower altitudes (I sometimes get tree jobs in L.A. including Malibu, Hollywood, Brentwood, etc...)

My advice...for what little it's worth, is to get a good used 044 / 440 and go through it with new oversize piston and cylinder, get a dual port muffler (or enlarge the stock single port...alot!) Buy the new Stihl Rollomater E S SuperLight bar 28" (PN# 3003 000 2238) and tune it up for the altitude...a bunch richer to make up for the lesser oxygen at those altitudes...then go cutting!

That setup is killer for mountain firewood...light enough to use all day long, yet enough power to rip through wood with authority...and you will save $$$$ over a brand new saw.

Best of all, you get to make it "your" saw, not just one you plopped down a plastic card for.

Have fun and Saw Safe

 

[Zombiechopper]

I would get a good used 044, MS440, 372XP and get it ported, milled with a popup. I'd want that saw making 210psi at sea level so you might still get 160+ up in the sky. The air is thinner, so you need the saw to gulp more of it in and compress it more

 

[jeeptj19992001]

you need to buy the special " mile high club saw

 

[mtngun]

milled with a popup. I'd want that saw making 210psi at sea level so you might still get 160+ up in the sky. The air is thinner, so you need the saw to gulp more of it in and compress it more

+1 You need a higher compression ratio to compensate for the thin air.

 

[JDNicol]

tune it up for the altitude...a bunch richer to make up for the lesser oxygen at those altitudes...then go cutting!

Surely you want to lean it out if less oxygen is available... to maintain correct fuel:air ratio


+1 on the higher compression.

 

[Bounty Hunter]

Surely you want to lean it out if less oxygen is available... to maintain correct fuel:air ratio


+1 on the higher compression.

Yep...less air, less fuel. I was thinking backwards, my bad.

As for higher compression, what happens when you use that 210psi saw at sea level...do you just richen it up and everything's fine? Does it become a PITA to start?

Just Wonderin'

Thanks :msp_thumbup:

 

[SteveH]

I live at 8500 MSL and cut from here on up to maybe 9000. I have no trouble with either of my saws. They work great. I have an 036 and a 441, so both a new Stihl and an older one. Never done a thing to them.

 

[hotshot]

Most definitely, if you don't richen it back up you will quickly fry the P &C.

 

[nate cutter]

To compensate a 044 at sea level a heavily modified or a larger displacement is needed a 460. I cut at 6000-9000 with a 372xp bb ported mm and it smokes a stock 440. Nothing against Stihl just against stock.

 

[Uglyhat]

Hey Uglyhat,

Welcome to the ArboristSite Forum...Interesting username, where didya get that?

The Ex didn't like my hat collection - winter caps, ball caps, hard hats, various helmets (yeah I hit my head on things a lot hehe). One particularly petulant but otherwise fine day she proclaimed "You must be the president of the Ugly Hat Club". Since her departure I've proudly taken this as my moniker on numerous forums, and was pleased to discover it available here.

This seems like an excellent forum. Thanks all ...

 

[Gologit]

Surely you want to lean it out if less oxygen is available... to maintain correct fuel:air ratio


+1 on the higher compression.

Good catch.

 

[BannonS]

We just bought the Stihl MS 250 BRAND NEW at a shop that was at about 6000 feet. We took it to our property at 9200 feet. It started, we cut one tree, then brought the saw down the next day to 6000 feet, then took it back to the property, at 9200’. Now we have been trying to start it for a second time, all day, to no avail. What are we doing wrong?? Now I have dinked with all the high altitude adjustments per the manual, but can’t get the thing to turn over. Haven’t really used a saw since the mid 70s and was thinking that they had probably evolved well in the meantime, but we are having bad flashbacks. Is there a formula for adjustments for this exact altitude? Did we buy the wrong saw? Sound advice appreciated greatly.

 

[pioneerguy600]

A saw will start at any altitude there is oxygen at, if it does not then there is a mechanical issue. The tuning is done after the saw starts to make sure the air fuel mix is correct for that altitude, if you set the needles in the carb as per the manual the saw would start. If it woin`t start you have some other problem that needs to be tracked down. All an engine needs to start is spark at the right time, fuel in the right ratio and compression of the mix. These are the starting points you need to check into, a flooded saw will take some time and effort to dry out so check that and spark while you have the plug out.

 

[rd35]

First thing that comes to mind is what pioneerguy600 alluded to in his post above. I'm betting your saw is flooded. When I have a badly flooded saw, I remove the spark plug and look into the plug hole to see the piston. I use the pull rope to turn the engine until the piston is all the way to the bottom (referred to as bottom-dead-center). Next I slowly roll the saw onto its side and continue rolling it until it is upside down with the sparkplug hole oriented to be the lowest point on the engine. This will allow any gas that has puddled in the engine pan to drain out of the spark plug hole. This will also allow the gas vapors to escape and fresh air to enter at the plug hole, therebv drying the engine out. A couple hours at least is required to let it dry out completely. I have had this work on several occasions to start a badly flooded engine.
Oh, and if this is not the problem...it doesn't hurt anything to try it. At high altitude with thin air, it is my understanding that saws (like any other engine) are prone to flooding. So their carburetors need to be adjusted leaner than at lower altitudes. The biggest problem with this is that if you transport the saw between two different altitudes, you need to re-adjust it every time you change locations. If not you will continue to have flooding problems at high altitudes and then at the lower altitudes (if adjusted for the higher) it will be too lean which can damage with cylinder and piston.

 

[Mauser]

I know nothing about Stihl saws (except that I absolutely do not want one, so I do not care about them), but I DO live over 7000 feet up, so I have some experience with the altitude.

I do not think you should worry too much about the limiter caps on current saws, every single one of them must have a way to remove the limiters and properly tune the machine. I do not think I will ever want a saw that thinks it can do this itself - just more over-priced, complicated and unneeded crap. Any decent dealer should be able to quickly and easily do this for you, and if you find one so stupid that he claims it is not needed, well . . . they ain't one of the decent ones!

My favorite mid-size saw that is also great at high altitude is the Echo 590/600/620 (all pretty much the same saw). The limiter caps are very easy to remove, neither the engine nor the exhaust needs modification (IMHO), and the saw is easy to tune for anyone with basic competence. Although I dearly love my CS-590, I would recommend the CS-620 instead for altitude.

The CS-590 has a somewhat unique carb that includes a combined high-speed carb circuit that utilizes both a typical H tuning screw AND a fixed bypass circuit that prevents some idiot from leaning out the saw so bad it burns up. Unfortunately, at 7,400 or higher, that fixed bypass circuit actually prevents you from leaning out the saw enough; I can get very close to the specified WOT RPM, but not quite. I think it is totally fine for 7000-8000 feet, but I wonder if it would be acceptable at 9000? I have not tried it that high, so I can only wonder. The CS-620 is a 'pro' version of the same saw, and one of the very minor changes to it is a different carburetor. That might justify the additional cost for real high-altitude use.

EDIT: a general apology to all for replying to this ANCIENT thread - I do not like to necro-post, but I did not notice the original dates. I sure wish they were more obvious on this forum!

 

[mudfly]

Sounds like you may be a good candidate to buy an m-tronic or auto tune saw. They automatically adjust for elevation and temperature.

 

[grizz55chev]

First thing that comes to mind is what pioneerguy600 alluded to in his post above. I'm betting your saw is flooded. When I have a badly flooded saw, I remove the spark plug and look into the plug hole to see the piston. I use the pull rope to turn the engine until the piston is all the way to the bottom (referred to as bottom-dead-center). Next I slowly roll the saw onto its side and continue rolling it until it is upside down with the sparkplug hole oriented to be the lowest point on the engine. This will allow any gas that has puddled in the engine pan to drain out of the spark plug hole. This will also allow the gas vapors to escape and fresh air to enter at the plug hole, therebv drying the engine out. A couple hours at least is required to let it dry out completely. I have had this work on several occasions to start a badly flooded engine.
Oh, and if this is not the problem...it doesn't hurt anything to try it. At high altitude with thin air, it is my understanding that saws (like any other engine) are prone to flooding. So their carburetors need to be adjusted leaner than at lower altitudes. The biggest problem with this is that if you transport the saw between two different altitudes, you need to re-adjust it every time you change locations. If not you will continue to have flooding problems at high altitudes and then at the lower altitudes (if adjusted for the higher) it will be too lean which can damage with cylinder and piston.

A flooded saw can be dried out in minutes with compressed air, take the plug out and blow the cylinder out for a few seconds, turn it over with the pull starter and repeat. Reinstall the plug , do not choke, set the high idle or hold the throttle wide open and crank it over, usually pops on 4 or 5 pulls. If you don’t have access to compressed air, just taking the plug out and turning it over to drain out the pooled fuel, and cranking the pull starter over will also work in a pinch. Just rember to not use the choke if you suspect a flooding issue.

 

[BannonS]

Thanks for all the swift replies. I swear to Christ I’m going to start that saw today, if it doesn’t start, any energy left will go to throwing that chain cover as hard as I can across the property.

 

[Ted Jenkins]

A high altitude saw that is bone stock will run at what ever place you want, but not well. My recommendation is a MS 660 and a 372 XP with as high compression as possible. A milled ported saw will run stronger than stock. A slightly raised compression along with a 5 to 7 degree timing advance will help very much. I do not worry about octane anyway, but high octane at high altitude does not mix. The saw can not then be used at sea level so it will be only a mile high saw. That is why I like the kit saws for this. Thanks