Echo SRM-266 Parts

The spark plug and the 50:1 oil are the only things the SRM-266 shares with the smaller trimmers. The carburettor, the air filter, the fuel kit and even the trimmer head are all a different number - which is why ordering "SRM parts" by the family name lands the wrong box more often than not.

The SRM-266 sits a full class above the SRM-225 and SRM-210. At 25.4 cc it is Echo's pro-grade homeowner-plus trimmer, and the parts reflect it: a bigger carburettor, a bigger air filter, and a head that holds more line. The RB-K112 carburettor is the same unit Echo fits across the 266 series - the SRM-266S, SRM-266T and SRM-266U, plus the PAS-266 power head, PPT-266 pole pruner, PE-266 edger, SHC-266 shaft hedge trimmer and HCA-266 articulating hedge trimmer. If a listing names any of those, the carburettor is the right one for your SRM-266.

The air filter, A226000472, reaches even wider: it is the same filter Echo uses on the SRM-280, PE-280 and the PB-251, PB-255 and PB-265 handheld blowers. That is useful to know, because a filter listed for a PB-255 blower is the correct filter for your SRM-266 - the fitment is decided by the number, not by whether the tool is a trimmer or a blower.

The SRM-266's carburettor is a Zama RB-K112, and it is the part most often blamed for a trimmer that will not run. In practice it is rarely the first thing at fault. A 266 that won't start follows the same cheap-part-first order as the rest of Echo's two-stroke range: stale fuel first, then the in-tank fuel filter, then the primer bulb and fuel lines, then the spark plug, and only then the carburettor itself.

The genuine 90137Y fuel system kit bundles the fuel lines, the in-tank filter and the grommet in one box, which covers two of those steps at once - it is the kit to reach for when the trimmer idles but dies under throttle, the classic sign of a perished fuel line or clogged filter. The full diagnosis sequence is on the Echo carburetor and won't-start pages.

The single most common mis-order on the SRM-266 is the trimmer head. The smaller SRM trimmers use the Speed-Feed 400; the SRM-266 and SRM-280 take the larger Speed-Feed 450. The reload mechanism is the same thread-through design covered on the line-loading guide, but the 450 is physically bigger and holds more line - fit a 400 and you lose capacity, fit a 450 on a smaller machine and the balance is off.

The 266 is rated for heavier line than the homeowner trimmers, so match the head to the right line diameter as well - a 25.4 cc engine will happily pull .095 in and step up to .105 in for brush, where a 21 cc machine bogs. For the string-side consumables that are common across the whole range, see the string trimmer parts hub.