v8titan
ArboristSite Operative
I know this is a chainsaw forum but this is good information about how much performance improvement you can get by moding an EPA approved muffler on a two stroke motor. I have one of those 21cc Echo hand held leaf blowers....about three years old. With an analog tach, I measured 7200 RPM full throttle with the factory setup. First thing I did on this mod was remove the red high speed adjuster limit to give me full carb adjustability. I optimized the setting to see what improvement I could get...just got a marginal improvement by making the mixture a little richer. Next thing I removed the muffler output baffle. Behind and inside the muffler box were three pencil diameter holes where the cylinder exhaust port mates up. I had to leave those alone. Here's where the restriction is.....at the output from the machine there is a small stamped out cover with a hole about the diameter of a single pencil....maybe slightly larger than 1/4 inch. First test, ran the unit with no output cover....very loud and needed to be tuned richer to run smoothly. Here's the big deal...the engine RPM went from 7200 to over 8100 just by letting her breath easier and get a little more fuel. Finished moding the cover to open the hole and the rest is history.
Tom
Tom
