15240 RPM with an Echo CS-510 ok?

[Buzzsaw]

Today I received a tiny tach/hour meter to go on my new Stihl Fs94R trimmer to track my accrued hours with it over the coming years. It's an awesome lightweight 2 stroke trimmer by the way. I decided to try it out on my Echo Cs-510 saw before I installed it on the trimmer.
The saw was purchased new in 2003 and I've cut approx 10 cords of wood a year with it since then. When new I removed the muffler baffles, deflector shield and spark arrester screen. I readjusted the carb to where the saw sounded right to me while cutting wood. It's running a 20" bar with sharp Oregon 20LPX chain.
When I checked it at WOT it hit 15,240 RPM on the tach. When I cut some 15" seasoned pine it fluctuated between 9,600 and 8,400 RPM. The saw started to bog when I pushed down hard and showed 6,600 RPM.
I must say that this saw really does scream and the muffler mod really brought it to life but 15,000+ RPM seems too much. I hate to mess with the carb settings since it cranks and runs really well and has been 100% reliable over the past 12 years.
What do you guys think?

 

[MichiganMadMan]

Sounds a little fast to me, but it's tough to tell without hearing it.

I'm wondering what kind of carb tune you are running.
I tune mine to "four stroke" if I lose the bite in the wood, so they start getting grumpy much past peak power. If you tune it so it "screams" at max revs, that is too lean. From your description it sounds like that is where your saw is tuned. I'd turn the mix richer until it is four stroking for sure just past where you want to run it. If you can find out the peak power RPM with a little web-searching, I'd have it go rich a few hundred RPM past that. More revs with no additional power is just beating stuff up for no reason.

I also let the saw do the work, and cut through the wood at its own pace. Doing a pull-up with the shark teeth digging into the wood won't do your saw any favors.

 

[Buzzsaw]

Originally Posted By: MichiganMadMan
Sounds a little fast to me, but it's tough to tell without hearing it.

I'm wondering what kind of carb tune you are running.
I tune mine to "four stroke" if I lose the bite in the wood, so they start getting grumpy much past peak power. If you tune it so it "screams" at max revs, that is too lean. From your description it sounds like that is where your saw is tuned. I'd turn the mix richer until it is four stroking for sure just past where you want to run it. If you can find out the peak power RPM with a little web-searching, I'd have it go rich a few hundred RPM past that. More revs with no additional power is just beating stuff up for no reason.

I also let the saw do the work, and cut through the wood at its own pace. Doing a pull-up with the shark teeth digging into the wood won't do your saw any favors.


It does 4 stroke out of the cut but sounds good while under load in the cut. I'm also running Motul 710 at 40:1.

 

[MolaKule]

Are you checking the speed on the chain or checking it at chain gear sprocket?

 

[doitmyself]

If this is correct, it looks like the no load rpm is about 13,000 rpm: http://www.arboristsite.com/community/threads/echo-cs510-rpm.11773/

Mola - the tiny tachs measure the engine rpm via the ignition "pulse". I have the big brother DTI 110 but seldom use it.

 

[MichiganMadMan]

Originally Posted By: Buzzsaw
Originally Posted By: MichiganMadMan
Sounds a little fast to me, but it's tough to tell without hearing it.

I'm wondering what kind of carb tune you are running.
I tune mine to "four stroke" if I lose the bite in the wood, so they start getting grumpy much past peak power. If you tune it so it "screams" at max revs, that is too lean. From your description it sounds like that is where your saw is tuned. I'd turn the mix richer until it is four stroking for sure just past where you want to run it. If you can find out the peak power RPM with a little web-searching, I'd have it go rich a few hundred RPM past that. More revs with no additional power is just beating stuff up for no reason.

I also let the saw do the work, and cut through the wood at its own pace. Doing a pull-up with the shark teeth digging into the wood won't do your saw any favors.


It does 4 stroke out of the cut but sounds good while under load in the cut. I'm also running Motul 710 at 40:1.


Seems OK then. I usually only get mine really cooking when I'm starting in on the cut, and then let it stay at peak power while it works through. I never understood the whole "rev monster" thing where guys run them well past peak power and then drop it on the wood.
Keep those teeth sharp, and hit the depth guides with a file every other sharpening and you'll do fine.

 

[JetStar]

You aren't running a muffler? They must hear you for quite a distance away. Put a tuned pipe on that sucker.

 

[Buzzsaw]

Originally Posted By: JetStar
You aren't running a muffler? They must hear you for quite a distance away. Put a tuned pipe on that sucker.


I'm running a muffler but it's gutted.

 

[bubbatime]

He is running a gutted muffler, aka the muffler mod. Very common mod that arborist make to get the most performance out of their saws.

As long as it is running good (as it has been for the past 12 years) I wouldn't worry about the RPM. Just dont rev it to 15K for no apparent reason.

 

[IndyIan]

Originally Posted By: bubbatime
He is running a gutted muffler, aka the muffler mod. Very common mod that arborist make to get the most performance out of their saws.

As long as it is running good (as it has been for the past 12 years) I wouldn't worry about the RPM. Just dont rev it to 15K for no apparent reason.

15k rpm means its running a bit lean though, I'd atleast look at the plug to make sure its a nice tan colour and not white...

 

[ironman_gq]

I've spent a lot of time playing with chainsaw tuning, found that most of them can handle 15k pretty well and it could be within factory spec depending on the saw. Most of mine call for factory max rpm between 13,500-15,000 depending on the saw. All of my modded ones (from basic gutted muffler to full work porting) run happily at 15,500 and can hit 16,500 if they get a little lean but too much of that and you start to scuff pistons.

I'd say with a gutted muffler your fine at 15,000 as long as it's still 4-stroking with no load on it. Heck my little 026 does 15k stock and with a little work can safely push 16,500 without being lean.

 

[Lapham3]

I've got a Jonsrud saw and Echo backpack blower-both over 30 years old and zero issues with either. I understand that one is working hard and the other is pushing air, but 50:1 synthetic Optimol and backed off a bit from 'max' rpm is my method

 

[Buzzsaw]

Thanks for all the insight and comments guys.