Echo cs 590,600,620 porting/mod/build thread

[Stump Shot]

Here's my take on a Echo CS590. Was laid out different from most saws in that it had a lot of intake and not a lot of exhaust duration. Here's it is by the numbers and how I worked through it.
Numbers as found;
Squish-.042"
Exhaust-112*--136*D
Transfer-129*--102*D
Intake-79*--158*D
Seeing that the intake was already as low as it is, I decided to leave the band alone and just tighten the squish. So I removed the gasket and machined .009" off the base to take the squish down to .020". Now to see how that changed it:
Exhaust-115*--130*D grind up to 1.160" from band and widen to 65% of bore diameter
transfer-131*--98*D grind up to 1.285" from band
Intake 81*--162*D leave alone
You can see by the comments after the numbers of which way and how much I decided to go. Lets see where that got us.
Exhaust-106*--148*D
Transfer-125*--110*D
Intake-81*--162*D
Timing advance 6*
Along with a healthy muffler modification this made it a much more powerful saw from new and capability of a pro saw.
Hope this gives someone out there some direction on doing their own.

 

[Agent Smith]

Here's my take on a Echo CS590. Was laid out different from most saws in that it had a lot of intake and not a lot of exhaust duration. Here's it is by the numbers and how I worked through it.
Numbers as found;
Squish-.042"
Exhaust-112*--136*D
Transfer-129*--102*D
Intake-79*--158*D
Seeing that the intake was already as low as it is, I decided to leave the band alone and just tighten the squish. So I removed the gasket and machined .009" off the base to take the squish down to .020". Now to see how that changed it:
Exhaust-115*--130*D grind up to 1.160" from band and widen to 65% of bore diameter
transfer-131*--98*D grind up to 1.285" from band
Intake 81*--162*D leave alone
You can see by the comments after the numbers of which way and how much I decided to go. Lets see where that got us.
Exhaust-106*--148*D
Transfer-125*--110*D
Intake-81*--162*D
Timing advance 6*
Along with a healthy muffler modification this made it a much more powerful saw from new and capability of a pro saw.
Hope this gives someone out there some direction on doing their own.

Did mine very close to your numbers. 106/126/82. One of my favorite saws in my collection

 

[Dieselnut77]

Sorry I didn’t see this till today. I’ve had a crazy week!

my final numbers are:
Ex: 100
Int: 80
Trans 126

trimmed cylinder down to get to .020” squish
And installed a ms 361 jet and the thring screams!!!
W/ a bar I’m hitting 14.4k rpm’s.
I need to make a different video of this thing now. I cut the cylinder installed the 361 jet and added a red beard saws air filter.

Very nice! Seems like these saws like longer blowdown, just like Mastermind (if memory serves) said in one of the porting posts regarding double vs. quad transfer cylinders.

 

[Dieselnut77]

Here's my take on a Echo CS590. Was laid out different from most saws in that it had a lot of intake and not a lot of exhaust duration. Here's it is by the numbers and how I worked through it.
Numbers as found;
Squish-.042"
Exhaust-112*--136*D
Transfer-129*--102*D
Intake-79*--158*D
Seeing that the intake was already as low as it is, I decided to leave the band alone and just tighten the squish. So I removed the gasket and machined .009" off the base to take the squish down to .020". Now to see how that changed it:
Exhaust-115*--130*D grind up to 1.160" from band and widen to 65% of bore diameter
transfer-131*--98*D grind up to 1.285" from band
Intake 81*--162*D leave alone
You can see by the comments after the numbers of which way and how much I decided to go. Lets see where that got us.
Exhaust-106*--148*D
Transfer-125*--110*D
Intake-81*--162*D
Timing advance 6*
Along with a healthy muffler modification this made it a much more powerful saw from new and capability of a pro saw.
Hope this gives someone out there some direction on doing their own.

That's good stuff. I still need to put it in big wood with my numbers that I have and see how she goes. I also have the option of using a base gasket again to give it a tad more grunt if need be.

 

[Dieselnut77]

That's good stuff. I still need to put it in big wood with my numbers that I have and see how she goes. I also have the option of using a base gasket again to give it a tad more grunt if need be.

Well, after chewing on what is posted above, I realized that I'd be pushing my exhaust number the wrong way, i.e raising it to 100*, not lowering it to, say, 103*-104*. Oops!

 

[harry398]

I ordered a 199 jet for the carb last week but it won't be here until Monday so I closed up the jet with some JBweld and will change it out next week.

View attachment 299529

Hey Ronie
I know this is old...but did that JB hold up on the jet?
Or did you replace it with Walbro OEM 86-578-1 Nozzle ?

I see you really got that thing running hard after doing port work, I am not going to port mine...I just want better adjustability of the high side. I really cant get much change on the high side.

I guess that extra hole is there to keep the saw running rich to save them warranty work?

Thanks in advance.

 

[Ronie]

Hey Ronie
I know this is old...but did that JB hold up on the jet?
Or did you replace it with Walbro OEM 86-578-1 Nozzle ?

I see you really got that thing running hard after doing port work, I am not going to port mine...I just want better adjustability of the high side. I really cant get much change on the high side.

I guess that extra hole is there to keep the saw running rich to save them warranty work?

Thanks in advance.

Welcome to the forum. I have the saw apart right now and I'll pull the cover off in a little bit and see what it looks like.

 

[Ronie]

I know this is old...but did that JB hold up on the jet?

I just looked at it and it looks fine but this saw has been ran very little. I have a 199 jet for it but I'm going to leave it as is for now. Pic is from a few minutes ago.

 

[mainer_in_ak]

Stock 620 works purdy good on 20 below zero meat cow. Dog team eatin good thanks to the torque of a 620. Best winter setting ive found on a saw in the last 15 years. Certainly better winter setting than my overpriced, pathetic stihl 881 magnum-less

 

[subiAL]

Ported my first saw today. Echo 590. Smoothed the airflow to the secondary lower transfer (dident do the primary because i was nervous about too much case volume causing spitback). Base gasket delete. raised and widened the exhaust.
Final numbers
Intake close 76
Intake open 80
EX 105
TRANSFERS 127
Blow down 22.
Wondering where else I can gain on this setup. All input Is appreciated thanks in advance

 

[Stump Shot]

Ported my first saw today. Echo 590. Smoothed the airflow to the secondary lower transfer (dident do the primary because i was nervous about too much case volume causing spitback). Base gasket delete. raised and widened the exhaust.
Final numbers
Intake close 76
Intake open 80
EX 105
TRANSFERS 127
Blow down 22.
Wondering where else I can gain on this setup. All input Is appreciated thanks in advance

FWIW the intake numbers, open and closed should match the same. Your wheel may be set off a couple of degrees or so.
Otherwise I will try to remember to take a look at my notes tomorrow, remind me if I don't get back to you.

 

[subiAL]

My original numbers before doing the gasket delete matched and I re zeroed before checking those. I did think it was odd though

 

[Stump Shot]

@subiAL
Here's what I did to make a 590 run and cut good for its owner.
Base gasket delete and .010" removed from base yielded a squish of .019".
Widened exhaust port to 65% of bore diameter and ported it out.
Matched muffler and intake to port openings.
Modded muffler with extra outlet.
Advanced ignition timing 6 degrees.
Defeated the limiter caps on the carburetor, possible I did some shaft thinning, can't really remember on that.
Finished ported timing numbers as follows.
Exhaust 106 degrees
Transfers Primary 125, Secondary 131 degrees
Intake 81 degrees
Don't recall doing much if anything with lower transfers.
Saw ran well. owner happy.
So much for my notes.
How one chooses to execute such a thing, is an uncontrolled variable, that changes from person to person and even job to job, with some variation in results, however, the overall general consensus is, these run fairly well ported. Being as your timing is pretty close, hopefully there is something you can take away from this that helps you on your quest.
Best of luck and happy cutting.

 

[Moparmyway]

This post above is a friggin great post !!

 

[TreeLife]

This post above is a friggin great post !!

Agreed, great information

 

[subiAL]

My saw is cutting like a monster. I need to either do the 620 carb or plug the hole in the high jet and do the 620 coil but I am very happy so far. I'll] look into some of the things you mentioned next time I open the saw up.

View this content on Instagram

View this content on Instagram