I have an Echo SRM-2100 trimmer and yesterday while using it I got to thinking it just doesn't have the power it used to. It's well maintained, freshly serviced and properly adjusted but has some use on it. I think I've had it near 10 years and got it used from a friend. With the amount of use I thought I might look into new rings or rings/piston. Found an OEM piston kit on eBay for $30 shipped, I would like to go that route but I'm wondering about the cylinder. I'm finding no over-sized piston or ring part numbers from Echo or OEM suppliers. SO my real question is; does anyone know if these engines are sleeved or plated and about doing a replacement or the piston/rings? Or what would be the SOP for rebuilding one of these small engines. The machine is still plenty capable of doing the work I have to do, so I don't want to tear it down unless the rebuild will be a straight forward piston/ring replacement. If I can find the answers about the cylinder I would just order the parts and tear it down when they came in, thus not having the tool be out of service any. I use it about 1-2 hours a week and trimming is no fun catching up once it get ahead of you. I bought a new mower this year and was considering buying a new trimmer but a good one is pricey at $400-$500. It would be nice to spend $30-$45 to get another 10 years out of this. I did search the net a little but didn't find the answers, hoped someone here would know.