Echo Chainsaws Carb Adjustments for Altitude

[kiteboarder]

Hi all, I have an Echo CS-620PW that I have been running for about a year. I live at about 5500FT above sea level. I never adjusted the carb for the altitude. I just pulled it out of the box and ran it. I just bought a CS-2511T and I’d like to be a bit more proactive about this one even before I run it the first time. It’s sitting next to me here, brand new out of the box.

I’ve watched a bunch of videos, read a bunch of articles and gone through a bunch of different threads about adjusting carbs. I understand how adjustments are done. I know now what I need to listen for and I know what to expect, with and without load. I’m even ordering a tachometer so I can double check my work.

I do still have some questions though:


1. The increase in altitude reduces the atmospheric pressure and air density…. so logically, IF Echo set my saw to 1100 FT above sea level at the factory, then in theory, running it up here out of the box should cause it to run rich, not lean. Right? So technically, running it out of the box as it comes will reduce performance, because of the increased lubrication, it was probably good for breaking it in. Right? I suspect the adjustments I have to do would be to lean it out a little bit.

2. I understand what the plastic limiter caps do and why they are there. I also understand they limit the amount of adjustment you can do. However, what I do not know if this… If I’m not modding my saws and only want to adjust for altitude, can I still adjust with those caps on? As in, will they prevent ANY adjustment at all? For example, say the dealer wants to make an adjustment. Do they remove them completely, or do they adjust with them on? I understand that keeping them on will prevent me from using the approach of turning them completely clockwise to start an adjustment from scratch. But if I don’t need to do that, then I might be OK.

I can’t take it to the dealer to adjust it for me because they are simply going to guess. I’m at 5500 feet and the dealer is down at about 800 feet above sea level and quite far from here. They’re not going to come up here to adjust them for me, so I better learn how.

It isn’t the first 2-stroke engine I adjust, but it would be the first gasoline 2 stroke engine. I used to do nitro engines all the time.

Thanks for the help.

 

[ammoaddict]

When I bought my echo, I think there was less than 1/4 turn adjustment with the caps. My advice would be to wait until you get your tach and try it with the caps and if you can't get the results you are looking for, remove them and try again.

Sent from my Moto G (4) using Tapatalk

 

[kiteboarder]

^^^ That's a great idea. Thanks. I've ordered this: https://www.amazon.com/dp/B0045L9GA0/?coliid=I19RXD5MVQTEHO&colid=PCR1AB8SWZV0&psc=1 - This is a good option for a tach, right?

 

[kiteboarder]

I mean, in terms of tuning the 2511T, based on sound I can tell if it's "4-stroking" or not... which should tell me if it's rich or not. So I could easily do a test with it warm. I can feel for throttle response in comparison to my experience and to my other saws (the get a feel for the low speed)... and then as far as slow idle goes, it does seem pretty close to what I would expect when I fired it up the first time. So I know it's not to far, but I would expect it not to be optimum for my altitude. Either way, I'm not cutting anything this week, so I can wait until the tach arrives later in the week. The 620PW I know is not performing as well as it could I think. But that might just be the fact that it's a larger engine and it's more highly affected by the "low-altitude" tune.

 

[SteveSr]

I mean, in terms of tuning the 2511T, based on sound I can tell if it's "4-stroking" or not... which should tell me if it's rich or not. So I could easily do a test with it warm. I can feel for throttle response in comparison to my experience and to my other saws (the get a feel for the low speed)... and then as far as slow idle goes, it does seem pretty close to what I would expect when I fired it up the first time. So I know it's not to far, but I would expect it not to be optimum for my altitude. Either way, I'm not cutting anything this week, so I can wait until the tach arrives later in the week. The 620PW I know is not performing as well as it could I think. But that might just be the fact that it's a larger engine and it's more highly affected by the "low-altitude" tune.

Based on other Echo threads these tend to come too lean from the factory so you might not be hurting yourself too much. Best thing to do is to just run it a while. You won't hurt it.

Your 5500' elevation will definitely make it richer but by how much is just a guess. A good way to tell is a good fast responding tach and whether it noticeably 4-strokes at WOT out of the cut.

I don't know about Echo limiters but Stihl allows 3/4 turn clockwise to lean it out for high altitude without removing the caps. Watch out if you do remove the caps as there is usually a fixed offset bias in the screw settings before the caps are installed. This throws out the window any published screw settings you might find in anything but a factory service manual.

 

[kiteboarder]

Talking about that. I would like to try and get a hold of FSMs for both of these saws. But anyway, thanks. That's what I figured with he altitude... that they would be running rich. I'm about to order a 20 inch bar and chain for my CS-620PW because I'm done with the large tree felling for now and any work for the time being will be on 18" and below logs. I just want to compact the saw a little bit. While I'm at it I'll give it a little cleanup and go over the filters and spark plug. Next time I get out I'll double check to see if they are 4--stroking during a cut. I know what to listen for now.

 

[Ketchup]

I live and work at 5800' and have been through 10 or so 2511t. My experience has been that they all start easily out of the box and run very nicely for a few tanks. After a couple weeks they start to go very rich. Clogged muffler screens and even Catalytic elements result if the saw isn't adjusted. Usually within a month I have maxed out the limiters. I gave up on the last stock saw last week and ripped out the limiters. Even once the limiters are removed I find these saws need frequent carb adjustment. I keep a special screw driver (ground to a finer blade to fit the needle heads) in my pocket so I can adjust in the tree. I believe an Echo tech has a tool to remove the limitiers and alter the settings, then replace the limiters, but I haven't tried that.

There is good info out there on the factory adjustment procedure with a tach. As stated above, start there and then remove the limiters once you have trouble. I have done this on all these saws I have worked with and ultimately all have been delimited (and MMed). I also find over time the settings change. Functional idle setting seems to rise and the L jet constantly wavers from rich to lean (dying at dropped throttle). The H jet mostly just richens. I love these saws, but carbs seem a bit cheap and unreliable. It appears that once the limiters are gone the H and L screws actually move in the carb body over time! Many times I have set the H at 3/5 out, only to find it almost back to 1 out a week of hard use later. It's annoying, but with a quick adjustment I'm back to work.

Just my experience.

 

[Cliff R]

There really isn't any such thing as a tune for any particular altitude. Just about everything showing up these days is pretty lean right out of the box and some has "fixed" jetting where the owner/operator can't do anything about it. The EPA simply has their hand in everything these days which includes the emission produced by small power equipment engines.

We tune saws for the conditions the are going to be used in. Altitude is part of the equation, but we tune the saw to run the best with the fuel being used in. For higher altitude operation any N/A engine will typically require custom tuning from the "base" settings.

Every year we go to Colorado Elk hunting and take along my Echo CS-37o. It takes a very slight "tweak" to get it up to par for the 10,600' where we camp. This simply involves increasing the idle speed slightly, leaning up the "L" mixture screw just a tad, and leaning up the "H" screw for best power in the cut. Takes about 30 seconds and we're good to go. Of course it is down on power some regardless of the tuning simply because when the piston moves down to fill the cylinder it's not taking in as much. Just the laws of physics with these things.

For Echo saws in general, we recommend removing the limiter caps and modifying them for full adjustments then pushing them back in place. Been doing this now for decades and we have zero issues with any of them. The newer models are pretty lean right out of the box, enough to "smoke" the P/C if you don't fatten them up a little, IMHO.

It also helps to fine tune them as you go thru the seasons and the air quality changes. For the most part those changes will be very minor and usually just a slightly tweak to the "H" speed screw to get them up to par for the days work at hand........Cliff

 

[ChipChomper]

I work at a variety of altitudes from 800 feet to 4000 feet so I'm adjusting the carb on my 2511t frequently. At 800 feet I had to back the high screw out about a full turn from stock adjustment for actually cutting in wood without without getting the saw to start getting hot and racing at idle. I will probably lean it a wee bit for primarily limbing work. I found the saw to be ungodly lean fresh-out-the-box so perhaps it would be pretty good for 5000+ feet imo

 

[Goofaroo]

Based on other Echo threads these tend to come too lean from the factory so you might not be hurting yourself too much. Best thing to do is to just run it a while. You won't hurt it.

Your 5500' elevation will definitely make it richer but by how much is just a guess. A good way to tell is a good fast responding tach and whether it noticeably 4-strokes at WOT out of the cut.

I don't know about Echo limiters but Stihl allows 3/4 turn clockwise to lean it out for high altitude without removing the caps. Watch out if you do remove the caps as there is usually a fixed offset bias in the screw settings before the caps are installed. This throws out the window any published screw settings you might find in anything but a factory service manual.

I moved from 1100ft in Oklahoma to 6900ft in New Mexico. For the first time I had to remove the limiter caps from my CS 450 to get it running right.