Fellin Feller
ArboristSite Member
I hear about people needing to break in a new saw. Is this necessary and if so how do you do it?
It seems hard to do since saws run at a high RPM.
It seems hard to do since saws run at a high RPM.
Do you have to "Break In" a new chainsaw?
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I've seen dealers from first start on a new saw hold them wide open.
Personally i always heat cycle new saws and rebuilds a few times.
Personally i always heat cycle new saws and rebuilds a few times.
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Same here. A few cuts, let it idle, let it cool down, and repeat. At least for the first tank of gas.
Canyon Angler
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+1 on heat cycling a new engine. Probably not needed -- and lots of people get away without heat cycling it -- but it can't hurt.
I've also heard you want to run a new engine at lots of different speeds. In other words, don't baby it (the rings might not seat) but also don't hold it WFO in hard dry oak for 5 minutes straight, either. Taking it on short excursions to top RPM under load will make sure the piston is traveling the full length of its stroke, and help seat the rings, and letting it cool down (by idling it so the fan stays running -- don't run it hard then immediately shut it off) repeatedly will help get everything grooving together in peace, love and harmony.
After doing that for a tank or two, I'd run it like I stole it. Take care to make sure it's rich enough -- you should hear a "four stroke flutter" when you run it fast under no load, and that flutter or burble should clean up under load. If it sounds like it "screams" when you open the throttle under no load, that may mean it's too lean, and running a saw too lean will burn it up. New saws, particularly big box store saws, are often tuned too lean to keep the EPA and repair shops happy. A friend of mine got a Husky from Home Depot or one of those places, and he let me run it when we were working together, and that thing was leaner than a dog in Ethiopia.
I've also heard you want to run a new engine at lots of different speeds. In other words, don't baby it (the rings might not seat) but also don't hold it WFO in hard dry oak for 5 minutes straight, either. Taking it on short excursions to top RPM under load will make sure the piston is traveling the full length of its stroke, and help seat the rings, and letting it cool down (by idling it so the fan stays running -- don't run it hard then immediately shut it off) repeatedly will help get everything grooving together in peace, love and harmony.
After doing that for a tank or two, I'd run it like I stole it. Take care to make sure it's rich enough -- you should hear a "four stroke flutter" when you run it fast under no load, and that flutter or burble should clean up under load. If it sounds like it "screams" when you open the throttle under no load, that may mean it's too lean, and running a saw too lean will burn it up. New saws, particularly big box store saws, are often tuned too lean to keep the EPA and repair shops happy. A friend of mine got a Husky from Home Depot or one of those places, and he let me run it when we were working together, and that thing was leaner than a dog in Ethiopia.
Ando81
ArboristSite Operative
I cringed when my local Stihl dealer gave my brand new 462 a pre delivery inspection. Fresh fuel and bar lube and it must have been revving wide open for about ten seconds I think. It felt like ten minutes. I’ve never revved anything brand new to full revs, just doesn’t seem right.
Start it, let it warm up a bit, tune it, put it in the wood. Get it loaded down good, get those rings seated properly.
first start it gets idled, blipped ,idled, blipped until warm then shut off...repeat that again then fine tune the carb. Pre warm the saw and put it into some wood letting the saws own weight do the cutting for a whole tank. After that it gets ran hard because any tune problems or mechanical problems should have surfaced before this point.
Not so much break in, but seat the rings.
echomeister
ArboristSite Operative
what happens if the rings don't seat?
The trick is just run it normal ,the only way to harm it would be to overheat it.
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Low compression, low power.
Canyon Angler
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On the other hand, if it's gonna blow up right out of the gate, better it blows up in the dealer's hands than yours...
Couldn't you harm a new saw by letting it idle for half an hour, glazing the cylinder and preventing the rings from ever seating?
echomeister
ArboristSite Operative
If they don't seat right away does that mean they are stuck or is it just a matter of time before they seat ?
I would assume it difficult to cause glazing in a chainsaw cylinder since their bores are very smooth and hard chrome or nikasil (even when new)with only very light cross hatching for oil retention plus they use a oil thats designed to burn away..hell maybe im wrong here but thats what I have gathered from my limited experience tearing them down and rebuilding them.
Stihl likes to use rings with a higher spring strength and ( will cut you) sharp edges
Caber seems to favor rounded or beveled edges and medium spring strength
Both work well with caber being claimed to seat instantly or very quickly with advertisements of more forgiving in reworked cylinders with possible rougher port edges while the stihl rings can take several hours of run time to fully bed into the cylinder and pistons ring lands. I have tried both and the hyway rings and find the hyway between both with the cabers well seated after 2 hrs the hyway after 3-4 hrs and the stihl taking around 10 in a chrome bore and think the cabers and hyway to not live as long as the stihl being a different grade of castiron and having the edges rounded will have a decreased sealing ability. That sharp edge is what wears against the cylinder wall as a sealing surface(beds in) but the drawback it is far more likely to hang up on a chip or widened port.
I'm not sure how a guy even would break-in a saw. It's not good do any real cutting at less than full-throttle. I think run it like normal, no massive logs, give it a chance to idle between cutting.
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All I do personally for any new or newly rebuilt saw is to tune it a little rich for the first 5 hours or so and go cut with it the same as I cut with older saws.
After the 5 hours or so, I tune it to what I establish is a correct by ear tuning- slight 4 stroking out of the cut under full throttle and cleans up in the cut.
What I do NOT do is pick tiny limbs only for those first few hours, or run at anything under WOT whilst the saw is working.
After the 5 hours or so, I tune it to what I establish is a correct by ear tuning- slight 4 stroking out of the cut under full throttle and cleans up in the cut.
What I do NOT do is pick tiny limbs only for those first few hours, or run at anything under WOT whilst the saw is working.
It'll break in faster if you go to WOT instead of 3/4.
I think most of the responses here illustrate that there are plenty of ways to break in a saw which ultimately work just fine. Many people reporting that their saws "wake up" after several tanks. I'm lazy and impatient, WOT and bury the bar. Get the job done.
I think most of the responses here illustrate that there are plenty of ways to break in a saw which ultimately work just fine. Many people reporting that their saws "wake up" after several tanks. I'm lazy and impatient, WOT and bury the bar. Get the job done.
