Echo 21cc Trimmer Mods (SRM-210SB, GT-2000, etc)

[Hulsty]

updates?

 

[gcdible1]

WOW, you're serious. I like it!

I'm curious to know what the flow differences are.

Thats what I was thinking...all scientific and shi:msp_wink:.

I had both the gt200i and the gt2000. Both ran great for me for several years.:msp_smile:

 

[osut362]

bump

 

[Team FAST]

I have some updates....but its been a while. Been busy with work, etc. Will try and post them soon.


Anyone know why my pics are no longer showing up? I hosted them on my picasa account.

 

[steve316]

pictures

Don't know why they are not showing up but would like the them. Steve

 

[Chris-PA]

I have some updates....but its been a while. Been busy with work, etc. Will try and post them soon.


Anyone know why my pics are no longer showing up? I hosted them on my picasa account.

Why don't you just upload them to AS directly instead of using a 3rd party site? With a 3rd party site link, if they change the URL even slightly then the old link is no longer valid and they're gone.

 

[LegDeLimber]

Has anyone run into these screws?
Theses came from an Echo pb-500 blower.
screw holes are indicated in second pic.
They were recessed into the body, in about 1/8" diam hole.
They take a small size "D" tool, the head is about 2mm.
Thought I found a tool for them but it was $50 before s&h
(area dealer wouldn't even discus it or those screws [..can't say that I blame them though])

The walbro ipl lists two different screws in this carb WLA-1-1
high & low, but neither one is like these and don't appear to be a fit.
( funny that the walbro page doesn't even display an image )
Found a site that had the correct part displayed,
but at $14 a piece !! (plus shipping)

hmm, was time to take a power tool to the carb.
couldn't turn them with a slot (tried 3 times)
and finally had to just dig down to get pliers on them
that nylock insert made 'em damn hard to turn.

these are why I wondered what pitch Stumpy used on his carb build.
http://www.arboristsite.com/chainsaw/232204.htm

 

[Chris-PA]

I was thinking about this thread this weekend while I worked on my 25 year old SRM-2410. The shaft broke on it last year, and I have been meaning to get another but had not bothered yet - then my neighbor threw out an SRM-2400, with a good shaft! They were both filthy and naturally I had to clean them up, and of course soon they were both pulled down completely. Mine was SN 20,xxx or thereabouts, and his was SN 161,4xx or so, and there were several major differences. My older engine was 1-ring, and had larger transfers (both are dual transfers) with a larger opening volume at the bottom. It also had some light scoring stripes, although it was usable. The amount of carbon in it, and blocking the exhaust port, was amazing. I must have run some real crap oil along the way.

The newer engine has 2-rings and lower volume, higher velocity transfers with a pocket-shaped profile to give better outlet angle and loop scavenging - it looked a lot like the jug in post #53 in this thread. The bore was in near perfect shape, so I wanted to use it, but sadly it had a significantly narrower exhaust port. Timing seemed about the same. The new engine had a very small Walbro carb (with a 20/64" venturi), while the ZAMA on my old trimmer was about 28/64" - pretty big for a 23cc engine!

So, I decided to open up the exhaust to about 56% of the bore (my old cylinder was only 50%), and used the newer jug. I figured the newer design lower transfers would help reduce case volume too. I removed the base gasket (only 0.010"), and drilled the 6 holes in the exhaust baffle from 0.235" to 0.250" (a 13% increase in area). I also used the bigger carb. All the carbon got removed from the piston, cylinder and rings, and I put it back together with all the best covers and parts from the two.

I can't believe how the thing runs! It's amazing what just a couple of tiny mods and the right parts can do. I've been using my ported PP338PT, and that has just a little more power, but it's heavy, poorly balanced and I hate the trimmer head (feeds string all the time). Clearly the old Echo was down on power at the end, but I don't think it ever ran like this. It's got the power now to keep the rpm up through heavier, thicker stuff so the line won't get caught. Now the Poulan can go back to pole saw duty.

 

[James Miller]

Iv never modded one of the echo motors but iv done a few older homelite bandit trimmer motors for friction bikes. I have one on the bench right now with BG delete and stuffed crank case Gona see how it runs and then maybe widen the ports. Never done any porting before so could be interesting.

 

[GeorgiaVol]

Thanks a lot. I was perfectly happy just working on my saws, now you got me thinking about the SRM225 over in the corner and the 2 extra powerheads I have. Now look what you did!

 

[Team FAST]

Looks like I need to re-post a whole lot of pictures. Here's where I left the project a couple of years ago...billet machined separate head on an Echo cylinder. Cases modified with four bolts attaching the cylinder/head assembly.



The cylinder after I cut off the original Echo cylinder head and machined it. The head will have an o-ring groove for sealing.




The cylinder head I machined.

 

[Team FAST]

Here's PHASE 1 which is the way I run the trimmer today.

Phase 1:
- Removed stock non-adjustable barrel carb
- installed blueprinted Zama adjustable carb from Echo GT-2100 trimmer...not straightforward....had to modify the throttle cable. The butterfly screw has been replaced with a low profile button head screw (better flow)
- removed stock choke assembly and replaced with aftermarket Go-ped style choke and velocity stack/K&N style air filter
- replaced stock CAT muffler with older style box muffler, ported.
- installed Trailtech tachometer

I've been using it like this for two years now. It runs STRONG, and is just as reliable. I loaned it to my neighbor a couple of weeks ago and he couldn't believe the difference in power/performance as compared to this Husky String Trimmer (which I have also worked on for him....see my Husky trimmer thread).

 

[Doskiez]

Ok I know this is resurrecting an old thread but this thread was my inspiration, and what I found out might be useful to those who have this trimmer. I was given an echo ES210 blower that was straight gassed and as I was ordering parts and looking at it it got me thinking about my trimmer SRM210 which shares basically the same running gear. I was hoping to get a little more power out of it so I decided to tear into it too. The main restrictions to these seem to be the carb, muffler, and base gasket transfer holes (Thanks EPA) to correct this I did the following.

• Doubled the size of the outlet slot in the muffler,
• Opened the exhaust port up about 2thou on each side and raised the top 1 thou (while removing what looked like a casting defect bump and channel on the top of the port.
• Cut the restrictor holes on the base gasket for the transfers (opened them up to the profile of the tranfer rather than being 3 little holes.
• Smoothed/ rounded the blunt edge of the seperation between the two transfers (cylinder brace)
• And finally but in no way least fitted a carb for an SRM 260 trimmer. the 260 carb is a direct bolt on, you can still use the factory filter housing (although I am going to try out the 260 housing for the larger filter) and it moves you from a 9mm venturi on the stock carb to a 12.2 mm

Testing the trimmer with all mods listed above and stock carb still showed improvement over stock (high speed jet was maxed out) but the addition of a larger carb made a huge difference. Revs much faster, holds RPM better through aggressive cuts and there is still adjustment left in the high speed jet to support further tweaking if wanted.
From this experience I think simply opening the base gasket transfers, opening the muffler up some, and the larger carb would still net good results on an otherwise stock trimmer.
Anyway thanks for the inspiration, I hope this helps some of you without access to a flow bench and machine shop, and I couldn't be happier with how this fairly simple mod turned out.

 

[James Miller]

I noticed a decent gain just splitting the muffler and pulling the cat plate out of my srm 225.

 

[Victor A Van Natter]

I also saw an impressive gain just cutting out the deflector plate in the muffler on an arm 225. Only problem now is it runs a bit rich. Used about 30% more gas than usual. But power definitely improved

 

[John Walsh]

What an interesting thread! Thanks for the science, and the mechanical artistry involved here. I'll bet it influences a lot of people to make mods to their 2-stroke equipment from mild to wild.

 

[John Walsh]

Howdy,

I've decided to start a thread to detail the various mods and testing I am doing on my Echo 21cc Trimmer. I know its not a chainsaw, but on the SRM-210 SB model I can put a 10" chainsaw bar attachement on and make it a pole saw. So there!

Basically, I wanted to use this trimmer as a test bed project to prove out my MOTA two stroke engine simulation software in preparation for using it on my much larger, much faster Kawasaki H1 500cc and H2 750cc two-stroke triple motorcycle restrorations. But I do love chainsaws as well. See my other threads Most of the mods I am making to this trimmer directly apply to the saws, so its worth the effort to document what I am doing.

I will update this thread with pics and data as I have time and make more progress.


For now, some background. I started out with a totally stock, totally reliable, and reasonably well tuned out of the box (I was surprised) Echo trimmer:

Front View:

Back View

Muffler view:

A couple of things right off the bat:
1. It has a fixed jet carb (no real mixture adjustment except Idle speed)
2. It has a very restrictive Catalytic Converter/muffler

Those Kawi triples were a hoot. My modded RD400F Yammie is a mini-hoot with expansion chamber exhaust, bored carbs and modded porting

 

[mexicanyella]

Mini-hoot! New vocabulary word!

This has been a fun read; thanks!

 

[John Walsh]

Mini-hoot! New vocabulary word!

I used to have a GT380 triple, which was not as “sporting” as the Kawasakis or Yamahas. A quick ride on a buddy’s RD350 (with surprise wheelie) prompted me to try building a set of expansion chambers.

Man, I miss being young and smelling two-stroke exhaust and hanging on for dear life, terrified. Missing that stuff and reading threads like this has prompted me to buy some Klotz BēNOL and run it in my PP333 trimmer. The smell brings at least some of the two-stroke euphoria back. Maybe I need to try some port mods on something too.

This has been a fun read; thanks!

I'm there with you, 100%, Nothing like the smell of racing castor oil. When I was 12y/o a neighbor had me race a quarter midget for him. I did well in the stock class and the following year he turned the stock car over to a friend's daughter and built an alcohol-burning, castor in the crankcase, highly modified QM for me that was pretty much always in a power slide around the blacktop oval track. That thing BARKED! I remember the GT380 as well. Nice bike! Ah, memories

 

[Okie294life]

FYI, many of those carburetors DO have an adjustable needle. There is only one needle and it is pretty well hidden, but you can make small changes. I have had little luck on those. As soon as you change something and adjust the carb, either the high or low end is not correct. If you find a traditional carb to fit then it might be worthwhile. Some of the handheld blowers use a two-needle carb on this engine, but I have never tried to swap one over. This should be a very interesting thread. There are SCADS of those Echos around, and most of the parts are interchangeable. Once you tell everyone what the best combo is, the prices will skyrocket on Ebay.

I bet there is no jet adjustment. A lot of these trimmers are using the new awesome rotary valve carb by Zama and they don’t have any adjustments, just throw away and replace. If you’re running more flow that could be a problem. If you’re serious about hp, you should look at a different head unit, or yank the engine off a larger trimmer.