Video: How to tune a chainsaw

[bowtechmadman]

Great thread Brad!

 

[Brian13]

Thanks Brad, this thread has been very helpful learning how to tune my saws. What do you do on a fresh rebuild to tune it during the break in?

 

[skidud]

Wow, them Ohio boys sure are sharp!

Superb video, I too was leery of my saw being too lean. I was guessing the sound it was making was the 4 cycling, but I wasn't confident enough to lean it out any. After running it like that all day, I got the worst headache from smelling the rich fumes all day. I'll never do that again. Thanks and great work.

 

[blsnelling]

Thanks Brad, this thread has been very helpful learning how to tune my saws. What do you do on a fresh rebuild to tune it during the break in?

I might run it slightly richer. But I still don't want it blubbering in the cut. I'm talking 500 RPMs at most. More important would be to not overload the saw and work it too hard in long extended cuts for a couple tanks. Let that piston break in a little first.

 

[Schipp]

Newb

"Thanks fer tha Vid! Will someone tell me what "WOT
" is? ok Thankee!" :msp_huh:
Schipp

 

[bluesportster02]

"Thanks fer tha Vid! Will someone tell me what "WOT
" is? ok Thankee!" :msp_huh:
Schipp

wide open throttle

 

[Schipp]

wot

"Thankee, Blue! Yea, I juss Googled it! Thats exsplains alot!" heh :msp_biggrin:
Schipp

 

[bluesportster02]

your welcome

 

[Schipp]

tuning the L & LA ?

There's more to tuning a chainsaw than just adjusting the high end, but this is a start. It also gives an excellent example of what 4-stroking sounds like.

In the first cut, the saw continues to 4-stroke, even towards the bottom of the cut. That's a little too rich. It should run clean all the way through the cut once under load.

After that first cut, I tune the H screw. I turn the H screw in clockwise until the engine peaks out and is totally 2-stroking. No 4-stroke at all. I then quickly richen the mixture back up by turning the H needle counter-clockwise. Immediately you hear the engine begine 4-stroking again.

The next cut you can hear the engine immediately clean out once underload, and stay that way for the entire cut. After that cut I rev the saw and you can hear that it is still 4-stroking at WOT. It's important to check for that after a cut, since that's when your saw will be its hottest and leanest.

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I'll try to make a more detailed tuning how-to video that includes L and LA adjustments.

"This is VERY helpful and interesting!!! I've shown this to several @ work! Thank you! Have u done a video on tuning the L and LA yet? That would be soo helpful. I went thru all 50+ ? pages of u'r posts and couldn't find it if u did.
Please let me know if did. :msp_thumbup:
Ok, Thankee again!!!

 

[wyk]

This video also helps a lot, Brad(Thanks!):

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[redunshee]

This video also helps a lot, Brad(Thanks!):

<iframe title="YouTube video player" width="480" height="390" src="http://www.youtube.com/embed/7jYUotkZorg" frameborder="0" allowfullscreen></iframe>

Couldn't bear to watch the whole video. If he is confused about the Lo and HI screws I'm out. Lo screw is always nearest the intake.

 

[wyk]

Couldn't bear to watch the whole video. If he is confused about the Lo and HI screws I'm out. Lo screw is always nearest the intake.

If he had them confused, the saw wouldn't behave as it did - and his saws in the rest of his videos would be poorly turned as well. Which, of course, they aren't.

 

[eriklane]

Proper high adjustment

So, am I correct in that you want it a little rich (4 stroking) at WOT on the bench, but that it shouldn't 4 stroke at all under load?

 

[FATGUY]

bingo

 

[eriklane]

Tune up fundamentals.

Basic stuff. Once you got the rules down, it's cake. Ran it for 3 hrs today, no problems. Now I know what too lean upper end sounds like, and, I did fiddle a little on the lower end, my saw wants to continue to turn, but, I can deal with that for now. No more bogging out low end either...And I hand sharpened it in the field, and it was great...a huge day.

 

[mictrik]

Good explanation!

I tuned my saw in this way I also used a Tach. When all was said and done the saw seemed to be perfectly tuned at about 100 rpm over the factory spec of 13500 for a Stihl MS-360 Pro. Here in the North East & I know many of you guys in the South experience very humid conditions in the summer. When tuning optimally in those hot, humid summer conditions you can be quite a bit off on cool dry fall or winter days. This has been my experience. So in the interest of operating the saw or any two cycle motor safely & optimally I always check the RPM at WOT & listen before proceeding to use the saw. All you need is a small screwdriver, trained ears & a cheap mini tach. You can drop the tach if your ears are well trained but I still think it is better with it.

 

[eriklane]

Tuning

I have to say that video sure helped. It's simple, but, if you haven't done it, it's 'complicated'. Listen for 4-stroking at high end (rich) or if the saw just seems to run too fast (too lean), and then smoking on the low end or dogging out (too rich) while cutting when the saw gets caught.

Once it's running right, on the low end, then adjust the idle speed. If you adjust the idle speed and then go into L adjust, you can mask problems.

 

[roger m]

awesome video Brad i used that technique today on my 460 after i installed a factory dual port muffler, it worked perfect 2 stroked while loaded and 4 stroked wot unloaded right after cut thank you very much!now i have to clean up all these cookies

 

[MacLaren]

awesome video Brad i used that technique today on my 460 after i installed a factory dual port muffler, it worked perfect 2 stroked while loaded and 4 stroked wot unloaded right after cut thank you very much!now i have to clean up all these cookies

Good stuff. Me likes it too. Brad has done a many a good vids. Huge assett to AS.

 

[blsnelling]

Glad I could help you