This is funny... Old thread but wanted to post.
I found this forum because of chainsaws and how everyone mods theirs. With the help here and reading, I successfully modded my first chainsaw, an Echo cs-370, did a muffler mod, exhaust port, and tuned it.
I started looking at my string trimmer and my leaf blower/vac (also echo).
After taking apart my leaf blower and seeing a cat on it I was sad, and the exhaust port is VERY restrictive. I passed thinking I couldn't adjust the carb since I didn't see any screws on it. I looked at the string trimmer and that had the same exact carb, but appeared to have a different muffler. It did NOT have the cat, but the exhaust port was very closed off. I ended up opening the exhaust port up quite a bit. Continued to read and found out that the carb that Echo uses has a HI-jet screw that can be adjusted which is located directly under the primer bulb. Problem is they cover it. I took a metal pick and removed the black plastic cap which took all of 5 seconds. At that point I can now adjust the hi side of it. I must say that now the string trimmer has some balls.
I then went back to the leaf blower. Because the muffler opening was slightly hiding the cat in the muffler I could not take a hole saw and drill it completely out in one swoop like I did with the chainsaw. Instead I used several size drill bits and several different angles and attacked it. Once getting 90% of it out, I then took my dremel with cutting discs and did away with the remainder amount in what was inside the muffler. If I knew how to open up the muffler I would have done it that way, but it appeared to be welded together, so that option of cutting it open or splitting it impossible for me. About 20 cutting discs later I now had a bunch of dust and metal inside the muffler. I simply washed it out and dried it. No more metal inside the muffler! I then attacked the exhaust port and drilled two smaller holes in it compared to the two small slits that it had. Adjusted the high side of the carb and now without a shadow of a doubt the leaf blower is a lot better. Before you could kind of hear this hollow gulp noise out the exhaust port. Now it sounds like an actual motor.
Output is clearly improved with both. I wish they didn't use this carb but glad I found out that it at least as a high side adjustment. Lowside idle can only be adjusted via the setscrew on top of the carb, not an actual low/high side on the chainsaw.
So just incase someone google searches for keywords.
I have the Echo srm-220 and the Echo ES-250 leaf blower. I saw MOST improvement with the leaf blower!
Thanks,
-Nige
