Echo cs 590,600,620 porting/mod/build thread
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Thank you sir.
Poleman
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Ok...finally back at it....
Well I didn't mess up the carb...that's good news!!!!!! Better yet the carb seems awesome!!!!
What I did was I did plug the H bleed hole but I used PC 7......it's thicker and more of a paste as the JB weld just ran down the tube. I tryed soldier and that's where I got in trouble as it wasn't a tight enough fit....even with sealer.....that's where I ended up taking out the main jet to retrieve it. Glad all worked out on that.
Saw started fine and at a higher idle. I increased the L until idle slowed to where I wanted it. At that point I did give a little more L then checked the H ....it was at 13,7 and I could richening it or lean it.....ADJUSTABILITY!!!!!!! FINALLY. I tuned to 14,2k where I think it should be!!!!???
This saw now has a adjustable carb instead of a closed or nearly closed H. I will get a better feel for the saw once I get it in some wood.
Pretty easy to do....block the H bleed and drill a .35mm hole and go!!
I still think David's idea is VERY good after really playing with this carb. Blocking it would be easier than plugging the bleed hole and it would get feed from the bleed holes and H & L circuit.....I think like the 670 carb is.
Red you may try closing off the main jet to see what that will do!! It would be easy to reverse.
Well I didn't mess up the carb...that's good news!!!!!! Better yet the carb seems awesome!!!!
What I did was I did plug the H bleed hole but I used PC 7......it's thicker and more of a paste as the JB weld just ran down the tube. I tryed soldier and that's where I got in trouble as it wasn't a tight enough fit....even with sealer.....that's where I ended up taking out the main jet to retrieve it. Glad all worked out on that.
Saw started fine and at a higher idle. I increased the L until idle slowed to where I wanted it. At that point I did give a little more L then checked the H ....it was at 13,7 and I could richening it or lean it.....ADJUSTABILITY!!!!!!! FINALLY. I tuned to 14,2k where I think it should be!!!!???
This saw now has a adjustable carb instead of a closed or nearly closed H. I will get a better feel for the saw once I get it in some wood.
Pretty easy to do....block the H bleed and drill a .35mm hole and go!!
I still think David's idea is VERY good after really playing with this carb. Blocking it would be easier than plugging the bleed hole and it would get feed from the bleed holes and H & L circuit.....I think like the 670 carb is.
Red you may try closing off the main jet to see what that will do!! It would be easy to reverse.
This is the hole I had jb weld in, I opened it up to 1mm along with swapping in a solid nozzle.
You saying you restricted the hole in the bottom of the nozzle? or block it completely off?
Either way seems it worked for you too.
Here you can better see the "bleed hole " in the bottom of the stock 590 nozzle, That is the only thing that needs to be plugged.
I opened my jb weld hole back to 1mm really close to stock.
Here is a shot from the top, I pulled the rubber "check" valve out for the picture.
The nozzle I used from the hda 191 had a relief cut and 2 feed holes in the side. The 191 nozzle also had a fiber/plastic check valve disc. not sure if one is better than the other.
You can see the 590 nozzle above only has 1 feed hole, that has to line up exactly with the carb body to flow.
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My first attempt was to use JB weld but that just oozed down the bleed hole and was very thin. I tryed a piece of soldier but I couldn't get it tight enough and it slid down to where I had to remove the main jet to get it out. I next used PC7 which is thicker and worked good. After it cured I then drilled it to .35mm.
Saw started good and had a fast idle and a boggy bottom. I adjusted the L to slow the idle down and increase the fuel supply. I got the idle where I wanted it and gave it a little more and it was right on.
Saw started good and had a fast idle and a boggy bottom. I adjusted the L to slow the idle down and increase the fuel supply. I got the idle where I wanted it and gave it a little more and it was right on.
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On the WG Walbros the groove around the main nozzle is a passage that feeds the low speed circuit from the high speed jet. So, when I see a groove around the nozzle.....I look for hidden passages.
Just the 1 hole. Inline with the high needle. You don't have much room for error lining up a .020 hole with a .060 hole blind..
It appears to act somewhat like a reservoir.. store just a bit of fuel before the vac pulls it through the carb bore.
Not so much an " pump" more like a reservoir. Has that extra bit of fuel handy to keep the high side in the range you set it...
The 670 carb just had a stright shot, no real fuel holding cavity. The tune would wander 400-500 rpm up top depending on how you stabbed the throttle.
Now with the mod 590 carb the "wander is in the 100-200 rpm range.. I believe since that extra cavity is full of fuel, it dosent have to wait for the carb to pump it.
I will find out if this theroy holds true once I try just plugging the main nozzle on the next carb.
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Joe, how much are you taking from the squish. My notes tell me to take .040" on a 11.5° angle.
paragonbuilder
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Are the 610 EVL twins any good? One just popped up on CL.
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Real smooth.......but not any sort of a hot rod.
Honestly Cant answer that one... Do it all by hand
Cut the jug till it hits, then cut the band till it fits...
I got roughly 7* on the piston..
No Base squish is .022-.025 the band dosent match the piston very well.
.040 seems like a lot... How much off the base???
Well It is an echo....
They have a following of the own. I hear they are pretty smooth.
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Notes say .054"
I thought that was too much too. It will almost freeport there.
I went back to .030".
.054 has to be really close.
Just did .038 on the xmas saw. maybe .040 would be ideal ish. plenty of drop, still safe from free port.
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Great read Joe. Wish I could understand what you guys are doing to theses carbs.
I get the theory, but don't really understand all of these little passages you speak of.
Definitely gotta give you a call one of these days.
I get the theory, but don't really understand all of these little passages you speak of.
Definitely gotta give you a call one of these days.
Thanks Al,
I'm just trying to learn these carbs, can't learn unless ya try.
Just send me a text first, as I keep different hours than the rest of the house.
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I ended up at .054 on Larry's 620, but that was using a new base gasket.
I'm the 590 I took .045 off.
Today I grind.....
Not sure what to do with the muffler. The early 600 just had an open can.
I ended up at .054 on Larry's 620, but that was using a new base gasket.
I'm the 590 I took .045 off.
Today I grind.....
Not sure what to do with the muffler. The early 600 just had an open can.
Hmm, they must have raised the entire port in the 620 jug..
As for the muffler, under the factory deflector. There is a large square recess, with a 1/2 ish tube, above that tube is plenty of space to open, providing a nice stright shot out. Also remove the bottom portion of the factory deflector, seems like plenty of outlet.
