Why my echo srm-225 trimmer starts but shut off when rev

SOURCE: Echo SRM 1501 trimmer has minimal fire. Feels very

If this is a solid state ignition ( black box mounted right next to the fly wheel)check for rust on fly wheel and coil/ignition.Sand with light grit sand paper if nessesary. Make sure to reistall with the same gap between the two parts.note the gap at this point could also be wrong.Also check to see if the clip inside the boot where the spark plug conects is not bent and that it is conecting properly. If this is a points ignition system then its basicaly the same steps.Clean contact pionts check plug boot for good contact. Or could be bad coil.Be sure you are using a plug with the propor heat range.

SOURCE: How can I remove Echo 230 SRM trimmer head?

on the head there is a u shape slot on the side. turn it until you can slide a small screw driver in it to lock the head. then loosen the nut on the bottom i do believe it is a left-handed

SOURCE: What is the correct ratio for fuel mix for a ECHO

A 50:1 ratio with 89 Octane fuel can be used in all ECHO 2-stroke equipment, provided the oil is ISO-L-EGD and JASO M345 FC/FD certified. ISO-L-EGD and JASO M345 FC/FD oil must be used with a mid-grade (89 octane) or premium gasoline in all 1997 and newer engines.
A 50:1 Ratio = 1 US Gal. 89 Octane + 2.6 fl. oz. ECHO POWER BLEND OIL
Echo Power Blend Universal 2-Stroke Oil can be used in all of our 2-cycle air-cooled equipment ever made. You may also use this oil in any other brand of 2-cycle air cooled equipment, but it should always be mixed at the 50:1 ratio whether or not it was a 32:1 or 16:1 etc. machine. This oil is the highest quality 2-cycle oil on the market today. There is no need to have more than 1 tank of fuel for your 2-cycle equipment any more.
Use only fresh gasoline with a minimum octane rating of 89 through 93 (mid-grade to premium) at all times. The gasoline suppliers blend mid-grade and premium gasoline with greater amounts of detergents and anti-oxidizing additives to keep the engines clean. Lack of these detergents and additives in a 2-stroke engine will cause a heavy build-up of varnish and gum deposits on the piston surface and ring grooves. Regular unleaded 87 octane or lower gasoline may not contain enough of the detergent additives that are needed in a 2-stroke engine to keep varnish, gum, and tar deposits from forming. Use of 87 octane fuel may shorten the life of the engine.

ALL TWO-STROKE OILS ARE NOT EQUAL!
ECHO POWER BLEND OIL, is manufactured exclusively for ECHO, Inc. and meets the (ISO) International Standards Organizations highest performance rating of ISO-L-EGD for Air Cooled 2 Stroke oils and is JASO M345 FC/FD REGISTERED. Years of research and testing have resulted in an oil that is fully compatible with fuels containing 10% ethanol and can be used in all air - cooled, outdoor power equipment 2-Stroke engines at 50:1 ratio. ISO-L-EGD and JASO M345 FC/FD rated oils must be used with a mid-grade (89 octane) or premium gasoline in all 1997 and newer engines. Always look for the JASO M345 FC/FD square logo and registration number to ensure you are using the highest quality 2-stroke oil for your ECHO product.
ECHO POWER BLEND OIL is made for high revving, (7,000 RPM and up) air-cooled 2-stroke engines that are E.P.A. and C.A.R.B. emissions certified. Make sure the oil has a EGD and FC/FD certification. Oils that meet ISO, EGA/EGB/EGC and JASO FA and FB are of lesser quality, designed for applications such as water-cooled boat engines, low RPM lawnmower engines, or snowmobile engines and should not be used in ECHO Engines. Prior to 1997, oils were not manufactured to these higher standards. Some or most of the oils were simply 30 or 40 weight 4-stroke engine oil with minimum amounts of additives. ECHO POWER BLEND OIL is the highest quality 2-Stroke oil available and will provide maximum protection against engine wear and carbon buildup.

SOURCE: i need an instruction manual for echo srm 225 weed

http://www.echo-usa.com/documentation.asp?Model=SRM-225&lang=E
Hope this link helps.

SOURCE: Echo srm-225 string broke off inside of the spool.

I solved the problem myself. I found the manual online and followed the directions that were given. Having the manual helped because it allowed me to know how to open up the spool without damaging it.