Should a chainsaw 4 stroke out of the wood?

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pops21

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I was doing some thinking today. Is a chainsaw that 4 strokes out of the wood but clears up in the wood in perfect tune? I know some just shoot for a few hundred RPMs below max reccomended RPMs. But which is the right and wrong way. Then there are people that start rich and do timed cuts leaning the saw out till the times peak and start dropping. So is the best answer
A. Four stroking out of the wood but clean out in the wood
B. Set to a few hundred RPMs below max recomended RPM
C. Do timed cuts till you have fastest time

Sorry if this has already been answered but I feel there is a grey area when it comes to the right tune in the wood. Especially with all the muff mods and porting being talked about. Cause I feel that throws another variable in the mix.
 
C is the best way to do it but for most people in the real world A will get the job done. Just relying on setting to an arbitrary RPM can be a short step away from a toasted saw.
 
4-stroking with no load on the engine may mean that it's slightly rich,
but that's certainly better than it being lean.
Doing a plug chop will give you a bunch more info. if you want to get closer to perfect. Timed cuts have too many variables.
 
For general work related saws go with method ," A", if you have enough run time on chainsaws and really know what you are doing method ,"C" would be better. Method,"B", might just toast a saw having carb or fuel problems.
Pioneerguy600
 
I tune by ear wanting a light 4 stroke out and as soon as it touches wood it clears up. But some of the newer saws are hard to hear the 4 stroke. What got me thinking about this is alot of videos that are posted on here and on youtube you can't hear the 4 stroke. Especially on modded motors.
 
I'd rather bury the bar and tune for peak RPM than do timed cuts. Especially since timed cuts can be helped a bit by tuning for high RPM and building more energy in the flywheel, which is the direction you don't want to go in.
 
A all the Way.

However most shops use a tach to specs. ??

I use a tach to establish a baseline for the particular saw. IF you haven't had any problems all these years don't change what you are doing.

:cheers:
 
I run mine a little rich. 4 stroke out of the cut and in till I make the saw work.

I don't want to hear it clean until it's under a load.

I'd just rather not take the chance on damage.I hate seeing aluminum transfer in a saw I like.
 
I run mine a little rich. 4 stroke out of the cut and in till I make the saw work.

I don't want to hear it clean until it's under a load.

I'd just rather not take the chance on damage.I hate seeing aluminum transfer in a saw I like.

Thats what I do. My saws are all work saws. I would rather them run a little rich and a touch slower, than lean and fast. Whats .01 seconds worth when you are cutting firewood?
 
Same here.

If it cleans up with just a light load, it's too lean in my book.

I don't like to wear out the carb screws with daily fussing, and temp and fuel variations can grab ya when you aren't paying attention.

Stay safe!
Dingeryote
 
Good responses, and yes, it's best to er slightly rich than lean, in all cases.

I've been cutting firewood since the mid-1970's, and have never smoked a P/C yet, or had any other engine "issues" related to lack of lubrication, EGT's, etc.

What throws a monkey wrench into this deal is that some modern saws have rev-limiting coils and retard modules. These items can mimic the "four stroking" that we listen for at no load, and the untrained tuner can end up too lean with the "H" screw and possibly damage the engine.

I have a couple of saws with rev-limiters. I start out with them noticably rich, and missing heavily, then sneak up on the tune by leaning them up and making cuts. With some, it's still difficult to tell exactly when you hit the rev limiter vs the ideal fuel setting(s).

For all my other saws, I set them for best power in the cut, and so they four stroke when the load is removed. They should "clean up" as soon is load is applied again. Basically, the "H" speed screw is your "rev limiter", and makes sure saw gets plenty of fuel to avoid going lean or running away when the load is removed.....Cliff
 
ok now im worried. i put a muffler mod on my new 460 and took it in to the dealer to have them adjust the carb. i know that they just hooked her up to the tach and tuned it to 13.5k. It flat out screams. do you think its running too lean?
 
A then C here, though not really timed cuts, I just know the saw well enough that if I'm not getting the performance I expect I look to the tune. This generally leads to a quick deuche of the air filter too. Seems after mod the saw is more sensitive to wanting all of that air.

Could someone give a simple explanation of why the saw runs leaner under load? Or does it?
 
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