ECHO Echo, Echo, Echo

[dahmer]

I've noticed on some of the Echos with catalytic converters, that they aren't tuned nearly as lean as, say, the 500 series are from the factory. My CS361W was very rich, even with the cat removed.

No cat in the 590.

 

[Nutball]

I've seen a cat in a 400 as well as the muffler inlet sized to match even the shape of the exhaust port. But I was surprised to find on the 352, no cat in the baffle tube, and the inlet was a big circle, so they done good on this one except for the front deflectors and spark screen. It could be running a bit rich. I know the 355 I still have NIB has the carb limiters showing both H & L set to maximum rich.

Any recommendations on what port mods to do then?

I find it interesting how they used sharp edges on the ports, so very minor scoring has appeared only inline with the ports on a low use well oiled saw. That's the only mfg flaw I can find with Echo

Seemingly no noticeable power increase with the muffler mod. I ran it at 100-200rpm slower in the test cut than stock, but it certainly had a noticeable torque increase running between 8900-9600 in 14" of ash.

 

[Battle Cross 2]

Merry Christmas (I'm guessing it's still Christmas day there? It's Boxing day here already!)

Thanks for the info & the photos!

Did you have to wind the H screw out very far after you made the mod?

Didnt change the tune at all. It was rich before and seemed to be happy set at the same spot after.

I just got a new one, I looked it over, and found the air filter to be very thick and restrictive. I have not run it yet, but I plan on finding or making a better filter for it. Also the vent leading into the filter box might need opening too. I say you should try to come up with a minimal temporary filter and make a test cut without the stock filter and see if there's improvement.

Any recommendations for filter media to try? I do know of all my saws the 355 filter stays cleaner then any other.

 

[Nutball]

My 271t filter stays pretty clean too. I don't know for sure if I've ever seen a saw (any brand) not get dust through the filter, but I haven't paid close enough attention. For long term use I was thinking I'd check a fabric store for something less restrictive, or taking apart another filter and modifying it to fit, likely a higher flow accordion shape one. For a short term test you might tape some scrap of low resistance fabric over the filter box and maybe the starter cover too just for a single timed cut.

Maybe I'll try that tomorrow with my 271t if I remember, but it isn't really modded much at all, so it might not benefit from more air.

 

[FergusonTO35]

I've seen a cat in a 400 as well as the muffler inlet sized to match even the shape of the exhaust port. But I was surprised to find on the 352, no cat in the baffle tube, and the inlet was a big circle, so they done good on this one except for the front deflectors and spark screen. It could be running a bit rich. I know the 355 I still have NIB has the carb limiters showing both H & L set to maximum rich.

That's how my 500P is. No cat or even a baffle, just a spark screen and small deflector.

 

[Nutball]

Unfortunately you can't really compare the 500 muffler to the 352 very well. The 352 is much like the 400, but bigger inlet size and no cat in the cat tube. The 500 like the 490 is an empty can with a pipe insert. It is interesting how there's random models without cats.

 

[dahmer]

Unfortunately you can't really compare the 500 muffler to the 352 very well. The 352 is much like the 400, but bigger inlet size and no cat in the cat tube. The 500 like the 490 is an empty can with a pipe insert. It is interesting how there's random models without cats.

I think the cat is determined by the number of sales per model, higher the sales the better the chance of cat. Thanks to regs.

 

[Mutley]

A large part of the reason is Japan and most, if not all of Asia have less strict emissions standards for small engines than the US and Europe do(strato saws aren't even required with standard carbs). We often forget that there's 120 million people in Japan, and that Korea, Australia, Phillipines, Indonesia, Thailand, Malaysia, and India are fairly good sized markets for mid-priced quality made small engine equipment that Japan has on offer, and this is without mentioning Africa and South America. So they were simply installing cats in to their saws while considering strato and electronic options in the near future. The fact they've gone so long without is astounding, tho.

We're getting new emissions laws as of 1st July this year. The government have decided to introduce them incrementally; marine engines & OPE are first cabs off the rank. The fines for importing non compliant stuff are significant too.

 

[Dub11]

We're getting new emissions laws as of 1st July this year. The government have decided to introduce them incrementally; marine engines & OPE are first cabs off the rank. The fines for importing non compliant stuff are significant too.

So is there muffler police hanging out in the woods there?

 

[dahmer]

So is there muffler police hanging out in the woods there?

You know how cops always check out muff.

 

[Dub11]

You know how cops always check out muff.

Hey I'm not sure about some of the rookies I see now ah days.......

 

[Drptrch]

Two of ours ; }}

Erik

 

[Mutley]

So is there muffler police hanging out in the woods there?

The laws only apply to new equipment sold by wholesalers & re sellers.

All the stores I visit have minimal, if any, non compliant stuff left on the shelves, whats left is pretty heavily discounted. Can't blame them, if they've still got any non compliant stock left after 30th June, they can't sell it.

What we do with it after we buy it isn't regulated yet. It is for cars, so you can bet it's on the way for OPE at some point.

 

[Nutball]

Anybody know where I can find an unlimited coil that will fit a 352? And a for a 490 while I ask.

 

[dahmer]

Anybody know where I can find an unlimited coil that will fit a 352? And a for a 490 while I ask.

@Red97 would be the one to ask on Echo.

 

[Nutball]

I did some tests on 490's air injection system. By plugging the carb adjustment holes and hooking up a pressure gauge to one of those holes, I found at full throttle around 2.3psi of boost in the carb box, . I also noticed in a couple revs and a single test cut it seemed to run slightly richer than the previous 3 test cuts in a row only a few minutes earlier, which surprised me. The test cut was right in the middle of the stock cut speed range, but I'd like to think it was slightly slower than it should have been. I also found that it seemed much more fine sawdust got trapped in around the carb and filter with those holes plugged. So much, that it might plug the filter in 1 tank of gas. I was cutting ash which always surprises me how much fine dust it sends flying. Also, I found this to be a torquey saw. At least it could still hold 2psi with the idle speed screw hole open, so it seems to have the ability to both add boost and blow dust out.

What I assumed was max power rpm was out cut by leaning hard on it and slowing it a good bit. It might not need an unlimited coil after porting, probably best to port it for torque. cut fastest between 6200 and 9500rpm

 

[Battle Cross 2]

I think Joe's porterd 490s run stock coils and those saws are nuts for 50cc.

Can't remember if that's a 28 or 32

 

[Piston Skirt]

I did some tests on 490's air injection system. By plugging the carb adjustment holes and hooking up a pressure gauge to one of those holes, I found at full throttle around 2.3psi of boost in the carb box, . I also noticed in a couple revs and a single test cut it seemed to run slightly richer than the previous 3 test cuts in a row only a few minutes earlier, which surprised me. The test cut was right in the middle of the stock cut speed range, but I'd like to think it was slightly slower than it should have been. I also found that it seemed much more fine sawdust got trapped in around the carb and filter with those holes plugged. So much, that it might plug the filter in 1 tank of gas. I was cutting ash which always surprises me how much fine dust it sends flying. Also, I found this to be a torquey saw. At least it could still hold 2psi with the idle speed screw hole open, so it seems to have the ability to both add boost and blow dust out.

What I assumed was max power rpm was out cut by leaning hard on it and slowing it a good bit. It might not need an unlimited coil after porting, probably best to port it for torque. cut fastest between 6200 and 9500rpm

Actually CS-490 (just as almost any ECHO since 1990's) has "air/dirt extraction" system. The channel that goes from the carburettor area to the fan ends up exactly in fan vacuum zone. You can check that on removed starter assembly and see how the duct is routed together with black plastic fan shroud.
The air to the airbox is fed through the opening below the carburettor - above the rear handle/fuel tank. CS-490 has a plastic induction noise silencer there which is actually removed in CS-501 for better airflow.
Basically by blocking extraction duct and removing induction silencer there should be some theoretical improvement with obvious dirty consequences

 

[Nutball]

I just reread you post, and it makes more sense now. I was just about to post how the design makes no sense! How can the 490 get +2psi in the air filter box when the flywheel is vacuuming air out? But both it and the 590 have their duct going to the intake side of the fan!!

Don't most other brands actually inject air off the outlet side of the flywheel? I wonder what would happen if the 590 was modified to do that? A big boost might be possible. I would think pressurizing the air box while leaking a much higher CFM than the carb sucks in would do a good job of both boosting power and blowing dust out. It might be worth a try sometime, but more surface area might be needed on the engine cooling fins to compensate for less air to it.

 

[Piston Skirt]

I just reread you post, and it makes more sense now. I was just about to post how the design makes no sense! How can the 490 get +2psi in the air filter box when the flywheel is vacuuming air out? But both it and the 590 have their duct going to the intake side of the fan!!

Don't most other brands actually inject air off the outlet side of the flywheel? I wonder what would happen if the 590 was modified to do that? A big boost might be possible. I would think pressurizing the air box while leaking a much higher CFM than the carb sucks in would do a good job of both boosting power and blowing dust out. It might be worth a try sometime, but more surface area might be needed on the engine cooling fins to compensate for less air to it.

Well... thing is this system is well thought out in most cases and it doesn't cause actual noticeable vacuum or pressure inside airbox anyway. They create actual directed airflow in the airbox to get rid of the debris and not the pressure/vaccum itself (think as CFM for blowers to MOVE the stuff). Living proof of "stuffing instead of sucking" are ECHO 361 vs 360 (355 in US) - the top handle unit sucks the air out of airbox, while 361 (rear handle version of the same engine) pushes the air in opposite direction. Guess what? Both have basically the same rated, measured and actual power

Generally on this topic - forced induction does not work too much on 2 strokes. But air/debris pre-cleaning systems do
There can be much debate about which one is more effective though but in my personal experience different people tend to have very individual and contradicting opinions.