If echo makes a saw that will cut as good as my 500i and runs as clean I’ll go buy one right now. You’re probably laughing about chainsaw emissions but the clean burn of the 500 is actually nice. I don’t stink nearly as bad after sawing with it vs other saws. I bought a 590 largely because of the huge number of raving reviews it gets and I quickly sold it. My Makita 6100 that’s another value saw cuts circles around the 590.
Try using canned gas instead. All I run is Echo Red Armor 50-1 and premium bar oil and I will say (tongue in cheek) that a stock 590 needs breathed on a bit to run well and it also takes about 3 full tanks of fuel before it develops good power. First thing I did (before I even started it) was, I pulled the muffler and removed the top baffle (under the deflector plate) which is kind of a PITA because it's spot welded on so you need to use a die grinder to remove the welds and I drilled (with my Dremel) 3 rectangular holes in the lower inside baffle, then I added 2 tight fitting rubber O rings to the carb inlet stub, one on the stub and one on the inside of the stock flooked air cleaner where the fixing stud goes through as the stock air cleaner has a bad habit of passing fines. I set the high speed mixture screw (after removing the limiter caps) to where it just 4 strokes free revving and it starts second pull and runs like a raped ape. I can actually do a full 20" bar rip cut in seasoned oak and it never bogs down at all, just keeps right on trucking. I did buy the oiled foam (Nick Stokel Stack) velocity stack air cleaner but have not installed it yet as the saw is running just fine now. I may at some point install the 5 degree offset flywheel key and a 620 ignition set as the 620 set allows a higher rpm but so far, it's fine as it is.
Removing the baffle and putting the slots inside the muffler really woke it up plus it has a mean, deep sound now, not obnoxious, just nice. Of course a sharp chain always helps too but then I grind a lot of chains for my arborist customers (as well as brush
chipper knives) so grinding chains is real common here. I usually have at least 50 loops that need sharpened at one time and mine are always razor sharp and the rakers set at 0.030. Have 2 chain grinders I mount to the welding table, one for grinding just cutters and the other for dropping rakers. One thin I never want to see is sawdust coming off a loop, I want to see real chips. Once any loop starts building pitch on the backside of a cutter, it's time to replace it with a new loop and I always have an extra loop with me, just in case.
I do use carbide tipped loops or through hardened and TIN plated cutter loops when cutting stumps for grinding as the dirt at the bottom of a stump will quickly dull an ordinary tempered loop. Problem with carbide tipped loops other than the cost is they have to be sharpened with a diamond impregnated aluminum rimmed wheel but the through hardened cutter loops can be sharpened with a conventional red wheel, just carefully. First responders and fire brigades use the carbide tipped chains when cutting through shingled roofs and nails for venting. I have the through hardened chain in bulk loops but the carbide tipped, no, I cannot afford the bulk loops of that.
I did leave the USDA spark arrestor in place however. Running the Red Armor canned gas I get no carbon build up in the muffler or the exhaust port or on the screen and the piston and the jug is pristine inside too. No score marks or buildup on the piston skirt at all and the plug is always light grey too. One nice thing about the canned gas is there is no exhaust stink at all and no smoke except on a cold start. I realize it's a bit more expensive but when you factor in the cost bottle oil it's really not that bad, especially if you don't run them constantly and I don't plus I can leave the canned gas in the fuel tanks and not run them for months and they start right up and idle just fine. In fact my Stihl's run better on canned gas than pump gas and the unopened canned gas has a shelf life of 5 years and 2 years in a saw and of course no carb or fuel line issues either. I even use it in my motorcycles when I put them up for the winter. Egas especially is hard on fuel lines and lets not mention carbs. Around here non e-gas is hard to find and when you do, it's super expensive, about on par with canned gas once you add the oil to it and pray it don't gum up the carb or rot the fuel lines. Too bad you sold it, I'm always on the hunt for another Echo, especially a used and not abused one. The two things I don't like about the 590 is the plastic chain cover and the crappy kill switch and to a lesser extent the clutch rim driven chain sprocket but that can be refitted with an insert drive clutch drum when the time comes and so can the plastic side cover with real captive bar nuts. Price wise I bet you paid a whole lot more for that Stihl than I paid for my 590 and your Stihl still needs a muf mod to let it run to it's full potential. I own 3 Stihl's, my 45+ year old 028WB and a 075 as well as an 090G neither the 075 nor the 090G has been started in years and both are devoid of any gas or bar oil. They sit on a shelf and look pretty and my wife wants me to sell them but they are old friends from a time when I owned a tree business so I just keep them. The 075 wears an early Stihl roller nose greaseable bar in 48 length and the 090 wears a 5.5 foot 2 man bar and both have .404 full tooth
chipper loops on them and both a surgically sharp as well and of course both are heavy and both sound like motorcross bikes when running I think at least. Been a long time since I ran them. Bought them both new when I bought the 028, many moons ago.
