ECHO SRM-225 string trimmer
The SRM-225 is ECHO's 21.2cc straight-shaft trimmer. Part numbers below are from ECHO's parts catalog for serial numbers U78312001001 to U78312999999. Older units have their own catalogs.
Specs and part numbers at a glance
- Displacement
- 21.2 cc
- Spark plug
- NGK BPM8Y (BPMR8Y in Canada)
- Plug gap
- 0.65 mm (0.026 in)
- Plug torque
- 112–150 lbf·in (130–170 kgf·cm)
- Fuel mix
- 50:1
- Trimmer head
- Speed-Feed 400, 99944200907
- Line
- 0.080 in (2.0 mm) or 0.095 in (2.4 mm), cut one 20 ft (6 m) piece
- Carburetor
- Z011-0GB, ECHO part A021005440
Find the model number
The serial number label is on the trimmer. ECHO publishes a parts catalog for each serial range, so the first part of the serial (for example U78312) tells you which catalog to use.
Parts and part numbers
Check the number against the parts list for your exact model before you order.
| Part | Part number | Notes |
|---|---|---|
| Air filter, double layer | A226001410 | ECHO parts catalog, U78312 serial range |
| Spark plug | A425000000 | BPMR8Y |
| Fuel filter | A369000470 / A369000480 | Catalog lists both; match the drawing to your unit |
| Purge bulb | P005003110 / P005003120 | Catalog lists both; match the drawing to your unit |
| Carburetor repair kit | P005004980 | |
| Speed-Feed 400 trimmer head | 99944200907 | |
| Starter rope 3 x 700 | P022008260 | |
| Tune-up kit (YOUCAN) | 90152Y | |
| Air filter kit (YOUCAN) | 90116Y | |
| Fuel system kit (YOUCAN) | 90251Y |
Tools you need
- Spark plug wrench
- Wire-type gap gauge
- Torque wrench (lbf·in range)
- Trimmer line, 0.080 or 0.095 in
- Gloves and eye protection
Maintenance and repairs, step by step
Start a cold engine
From the ECHO SRM-225 operator's manual. For a warm engine, skip the choke and don't hold the trigger fully open.
| 01 | Move the stop switch forward, away from STOP. | |
| 02 | Move the choke lever to COLD START. | |
| 03 | Pump the purge bulb until fuel flows freely in the clear return line, then 4 or 5 more times. | |
| 04 | Lay the trimmer flat with the head clear of everything. Hold the throttle handle, squeeze the trigger fully, and pull the starter quickly until the engine fires, 2 or 3 pulls at most. | |
| 05 | Move the choke to RUN, squeeze the trigger fully again, and pull until it runs. Let go of the trigger and let it idle for a few minutes. | The head must not spin at idle. If it does, see an ECHO dealer. |
Clean the air filter
Inspect daily. Replace every 3 months.
| 01 | Close the choke (COLD START) so dirt can't fall into the carburetor. Brush off the air cleaner area. | |
| 02 | Remove the filter cover and brush out the inside. | |
| 03 | Brush the filter lightly. Soak a very dirty one in water and detergent, rinse, and let it dry completely. | Replace it (A226001410) if damaged, fuel soaked, or the rubber edge is out of shape. |
| 04 | Fit the filter in its case and refit the cover. |
Reload the Speed-Feed 400 head
When the line runs out.
Safety Wear gloves. The cutoff blade on the shield is sharp and the gear housing can be hot.
| 01 | Cut one piece of line 20 ft (6 m) long, 0.080 or 0.095 in. | Never use wire or metal cable. |
| 02 | Line up the arrows on the knob with the eyelets. | |
| 03 | Push one end through one eyelet and out the other until both sides are even. | |
| 04 | Finish winding the line in as shown in the instructions for the Speed-Feed head. |
Replace the spark plug
Inspect every 3 months.
| 01 | Remove the plug and check for fouling or a rounded center electrode. | |
| 02 | Clean it or fit a new NGK BPM8Y. | |
| 03 | Set the gap to 0.65 mm (0.026 in). | |
| 04 | Tighten to 112–150 lbf·in. |
Troubleshooting by symptom
| Symptom | Likely cause | What to do |
|---|---|---|
| Won't start | Not primed, or old fuel | Pump the bulb until fuel flows in the return line, plus 4 or 5. Use fresh 50:1 mix. |
| Head spins at idle | Idle speed too high | ECHO says to readjust the carburetor or see a dealer. Don't use it until fixed. |
| Bogs down | Dirty air filter or fuel filter | Clean the air filter, check the fuel filter. |
| Line breaks a lot | Wrong line size | Use 0.080 or 0.095 in line. |
Owner's manuals and parts lookups
These go to the maker's own sites.
- ECHO manuals and parts catalogs Search SRM-225; pick your serial range
- ECHO parts lookup
Something wrong or missing?
Tell us the full model number on your engine and what you found.