Tuning a saw for milling

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Pete,
Thanks a lot for the detailed response. I think I'm understanding what needs to be done but not certain of the different sounds. I remember watching the video above and getting a feel for the difference in sound from 2-stroke and 4-stroke a month or two ago. Won't know for sure until I do it in person.

I've taken a break from milling for the winter and will give tuning a try in early spring. Thanks again.

BOA

Hey, no problem hope it helps. If you need more help consider this:

A trick with model engines I used, pinch fuel line to starve of fuel at idle. If engine speeds up and dies than you're at a good tune. Should be a noticeable change, no change at all than too lean. This works for checking tune at idle pretty well. With a saw could listen to it as it runs out of fuel or needle nose pliars reach in to pinch line.

Remember when you richen the oil/fuel mix with more oil, you're going to richen carb. I don't recall on mine how much richer than factory I'm running. Want to say around half a turn on both. Had the limiters set so they'd stop at the perfect tuned and left plenty of room to richen more. Easy to get things back that way, than one day I couldn't get it leaned enough so had to reset it, think I switched oil brand.

Youtube vids are great from reputable source, just remember "fat is where it's at", LOL. AKA, just a tad rich. I hardly every touch my carb and I mill off an on all yr. Some days it could be small tad richer or small tad leaner, but still in the range of an ok tune. I think when you tune more on the lean side you run into having to adjust more often. Don't forget you'll lose power when you get too lean just like too rich. Shoot for the middle. When you check for in the cut, make sure you've go something big enough that'll actually load the saw. I mentioned can barely tell in some soft woods or small logs. If that's all you mill than tune for that, but mine only really just but steadily sings in med large logs.

When I'm not milling, my saw doesn't quite have the power or snap to it but I don't bother to re tune as it's mainly a milling saw where it runs a perfect tune for that loading. It does cut ok, just ever so slightly noticeable.
 
I have to say, if you have a 20 degree temp swing, you'll be ok.
However, if you tune in fall, then go to cut in the snow at 40 degree swing or more, you are going to be lean. No question about it.

Use a tach, noise, how it cuts, anything, but re-tune the saw in the cold weather (especially the big saw for milling).
 
I don't think anyone posted this yet, but this guide here is one of the best you'll find on saw carb tuning:
http://www.madsens1.com/saw_carb_tune.htm

Mind you, their guide is for crosscutting. You don't want to tune the saw too fat, or too lean. If you tune it too fat you'll get a lot of carbon build up and that can ruin the jug/slug, and if you're too lean, well you'll seize it.

You will want it a bit on the fat side (rich). Another way you can see how it is tuned, is to shut it off while it's in the cut, (but kill it fairly soon, don't cut it off towards the end of the rip because then the saw is hot. Try and make sure the saw is fairly cool.) Anyways, kill it when its at full tilt under load, and pull the spark plug/examine it. You want a milky chocolate brown color, perhaps a bit on the darker side for milling.

What saw are you running, what length bar, what octane gas (ethanol/non-ethanol).

Tuning the saw there are some prerequisites besides turning the adjusters. You want to make sure that the gas tank is full. You want to make sure that the air filter is clean. And you want to make sure that the saw is warmed up. If your saw has a winter/summer flap thingy-ma-bobber, adjust it accordingly. For Stihl, they recommend that above 50*F you are in summer mode, and below you are in winter mode. A tach is nice, but not crucial. Watch a few videos to be able to listen for the four stroking.

Also, if you have a rev-limited coil, it could be running lean, but sound like it's fourstroking.
 
I don't think anyone posted this yet, but this guide here is one of the best you'll find on saw carb tuning:
http://www.madsens1.com/saw_carb_tune.htm

Mind you, their guide is for crosscutting. You don't want to tune the saw too fat, or too lean. If you tune it too fat you'll get a lot of carbon build up and that can ruin the jug/slug, and if you're too lean, well you'll seize it.

You will want it a bit on the fat side (rich). Another way you can see how it is tuned, is to shut it off while it's in the cut, (but kill it fairly soon, don't cut it off towards the end of the rip because then the saw is hot. Try and make sure the saw is fairly cool.) Anyways, kill it when its at full tilt under load, and pull the spark plug/examine it. You want a milky chocolate brown color, perhaps a bit on the darker side for milling.

What saw are you running, what length bar, what octane gas (ethanol/non-ethanol).

Tuning the saw there are some prerequisites besides turning the adjusters. You want to make sure that the gas tank is full. You want to make sure that the air filter is clean. And you want to make sure that the saw is warmed up. If your saw has a winter/summer flap thingy-ma-bobber, adjust it accordingly. For Stihl, they recommend that above 50*F you are in summer mode, and below you are in winter mode. A tach is nice, but not crucial. Watch a few videos to be able to listen for the four stroking.

Also, if you have a rev-limited coil, it could be running lean, but sound like it's fourstroking.
A lot of good jnfo coming in thanks guys. I haven't messed with my saws recently it's been like 0 degrees here,
But I'm eager to get out there once the weather breaks.

I have been running a practically brand new ms 660 with a 36" bar. I've milled a few cherry logs ranging from 20 to 29" diameter so far. Never even thought about tuning my saw because I'm a newb when it comes to milling. I soon found out I needed a aux oiler due to dulling chains and I did that at the end of the fall last year.

Fwiw I was conscious of giving the saw breaks in between each pass by letting it idle. Tried my best to prevent it from getting too hot during milling. As for fuel I run 40:1 with 93 octane ethanol fuel. I found some crazy racing fuel at a local Sunoco that's ethanol free but it's some insane 100 plus octane. Not sure if that's good for a saw or not?

I recently purchased an 076 from a member on here and plan on using that exclusively for slabbing. I'll be using the 660 more for smaller diameter milling using a 25" bar. Thanks again for all the info and help guys!
 
The rule is, "When in doubt, go richer. Never go leaner until you are SURE you are too rich." Rich will not overheat/ score/ gall. Too lean will scream, idle too fast, have no power, die at idle, hard start, etc. Too lean is NOT always carb, it CAN BE boots/ bolts/ screws/crank seals/ gaskets. Hope this helps. (the OTHER rule is "If it ain't broke, don't fix it"
 
Fwiw I was conscious of giving the saw breaks in between each pass by letting it idle. Tried my best to prevent it from getting too hot during milling.
One of the best ways to do this is to sharpen often.

As for fuel I run 40:1 with 93 octane ethanol fuel. I found some crazy racing fuel at a local Sunoco that's ethanol free but it's some insane 100 plus octane. Not sure if that's good for a saw or not?

The main benefit of using higher octane is because as soon as it leave the refinery the octane rating starts to drop and the older the gas and the more air it is exposed to the lower the octane. Starting out with a higher octane means you can on average store it for longer and it should be OK for longer. If you are going to use it right away it won't make much difference or hurt the saw,
 
One of the best ways to do this is to sharpen often.



The main benefit of using higher octane is because as soon as it leave the refinery the octane rating starts to drop and the older the gas and the more air it is exposed to the lower the octane. Starting out with a higher octane means you can on average store it for longer and it should be OK for longer. If you are going to use it right away it won't make much difference or hurt the saw,
So would you say it's worth spending the extra coin on that racing fuel? It's significantly more expensive but for as little as I mill wouldn't make too much of a difference.

I'm referring more to the fact that it's the only ethanol free fuel in my area not the extra octane. Thanks.
 
with all the so-called "Mini Tach" s being sold out there for $15 to $200, how does a newb find the right one for tuning the big Huski?
 
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