Elevation changes...

[Universe]

I am moving from Courtenay BC to Grande Prairie Alberta. My saw gets use up a mountain here, but Grande Prairie is 669 m (2195 ft) above sea level. Would the saw require adjustment?

 

[skwerl]

Most likely. Your saws will likely run leaner at the lower elevation (more oxygen in the same volume of air) so you may need to richen them up a tad, depending on how big the elevation difference is.

 

[West Texas]

Yep, has to be a tad more gas in the mixture, give the L jet a tweak CC and the H jet about 1/8th or 1/4 CC. The key to the L jet is how it starts and how rapidly it accellerates without hesitaion. The key to the H jet is how it runs 'in the cut' after getting a 4 cycle at max rpm out of the cut. Normally if there is a small amount of 4 cycle sound out of the cut, it will run smoothly in the cut under load. I'm at 5500 to 6000 and I make those changes in the clockwise direction when I bring them up here from the flat lands.

 

[TimberPig]

As you go up in elevation, the air becomes less dense, thus contains less oxygen for a given volume of air. This will cause your saw to run rich as you go up in elevation.

Temperature works in reverse, colder air is more dense, and thus has more oxygen in a given volume of air.

The other kicker is that on the island, the humidity is high, while in Grande Prairie, the humidity will be much lower. Moisture in the air will lean the mix out somewhat as it displaces oxygen as well.

All in all, you will probably end up slightly rich, but a quick visit to a saw shop In Grande Prairie to get the carb retuned will fix you up if you aren't confident tuning it yourself.

Good luck with the move. Heading to work in oil and gas are you? Or is there another reason to move up there?

 

[Universe]

Thanks. Oil and Gas. Reservoir Evaluation Wireline.

Does the 353 have caps on those screws?

 

[TimberPig]

Yes it will. The easiest thing to do is nip off the tabs from the caps, and then they will turn fully.

 

[ShoerFast]

I am moving from Courtenay BC to Grande Prairie Alberta. My saw gets use up a mountain here, but Grande Prairie is 669 m (2195 ft) above sea level. Would the saw require adjustment?

Universe

I'm with TimberPig on this, good sound advice!

If I may add, at altitude, you can get away with a lesser quatity gas, going lower, you may want to run the higher grades.

As a rule, the more hight , humidity or heat, the leaner the mixture needs to be, as there just isant as much air, but the same tune rules apply. (everything stays the same ratio)

Kevin

 

[Lakeside53]

I'm confused by replies by some of the guys that know the correct answers... I read it as you're moving from a low altitude (but occasionally use it up in the mountains) to a higher altitude, and some guys are saying you need to RICHEN the mixture? I think the opposite - leaner for higher...

..but 2195 is barely high so you probably don't need to do hardly anything, unless you haul it up the Alberta Mountains...

And yes, as Tiimberpig says, take it to your local saw shop in Alberta and have them help you out...

 

[TimberPig]

Since he is going up in elevation, changing humidity, and potentially temperature at which the saw is operated as well, the screws could end up moving leaner, richer, or staying where they are. That's why I simply suggested he find a dealer there and have it set correctly, as it is much quicker than guessing. For the elevation gain, it needs to be leaned out, for lower temperatures it would need to be richened, and for the reduced humidity it would need to be richened. The exact degree to which this will affect the adjustments is tough to quantify without actual numbers for temperature and humidity changes.

The elevation change from sea level where it is currently set for, to 2195 ft, will require a significant adjustment. Yes it isn't particualrly high elevation, but it is still a 2200 ft change in elevation. Who knows, maybe he'll get lucky and the elevation change will be cancelled out by the temperature and humidity changes. A quick run to the dealer will be much simpler.

 

[Lakeside53]

I don't find 2000 feet to require "significant" changes... maybe a touch... maybe. If anything is required, I bet the saw stays within its limiter cap ranges..

I'd just use it to cut wood...

 

[TimberPig]

The saw will likely still run fine, unless he tries to run it in cold temps with it adjusted for the much warmer, humid temps found on the coast. For his own peace of mind, it is likely better to simply have the adjsutments checked.

I guess because saw engines are in a much lower state of tune they respond much less to changes in elevation than do more highly tuned sled and dirtbike motors. On those, each 1000 ft ends up being a jet size, although with mixture screws, a small turn of the screw makes a jet size change, so it's not like it will require multiple turns of teh screws or anything.

No big deal, just have the shop check the tuning, especially if he does end up running it in colder temps.

 

[Universe]

Colder temperatures will DEFINATLEY happen, where I'm moving. I'll have it tuned when I move, maybe once more near winter.

 

[TimberPig]

Colder temperatures will DEFINATLEY happen, where I'm moving. I'll have it tuned when I move, maybe once more near winter.

I know that it gets much colder there than it does on the Island, but you only need to have it tuned for winter weather if you're actually running it then. If you don't use it during the winter, then it doesn't need to be retuned for winter operation. From what I recall, most of your use was for mountain bike trail building, which is normally done in that region during the spring, summer and fall, not mid winter when it is frozen and snow covered. If you plan to cut any firewood during the winter, then it would need retuning for the cold air. The best is to learn to tune it yourself, but having the dealer there check it is a better plan if you want to be safe because you are unfamiliar with how to tune it yourself. It's not hard, but does require a tachometer or an experienced ear and feel for how it should respond.

 

[Universe]

Winter is the best time to build trails since you aren't riding as much. If there is little snow, then the building is on. Summer is for riding, not so much building trails

 

[TimberPig]

Winter is the best time to build trails since you aren't riding as much. If there is little snow, then the building is on. Summer is for riding, not so much building trails

Have you worked in the kind of temperatures you are going to experience in winter in Grande Prairie? Not to mention slogging through snow to work. The only good thing about snow for trail building might be that logs and stuff slide easier if you have to drag them. It's not my idea of fun to go cutting in -20C, when I could do it in +10C when the ground is too wet for riding anyhow. The soils in that area are largely silt and clay, which make riding a real PITA during breakup, aka perfect time to build new ones.

 

[pinus]

At -15 an below celsius the saw will scream (no 4 stroking) and needs a litle enrich by the H screw, at least my one.

 

[wradman]

Don't Screw Around

save yourself a cylendar spend $120 and go buy a tach
DO NOT SET THE CARB UNLESS YOUR AIRFILTER IS CLEAN,THEN USE A TACH, I SET MINE AT ABOUT 12,500 WITH THE BAR AND CHAIN ON!

 

[Universe]

Well if its -20 then I probably won't be going out. Everything is within reason

 

[TimberPig]

Well if its -20 then I probably won't be going out. Everything is within reason

Like I say, I doubt you'll be doing much trail building in GP in the winter, as a good portion of the winter, it stays below -10C as a high, and extended periods of -20C isn't anything abnormal. It's not like the coast, where it might be wet, but it isn't really cold. GP will be cold, but dry, at least until you get wet from your body heat melting snow and sweating, which is bad news in that kind of cold weather.

 

[Universe]

Well I'll be working outside in the winter