So I finally found some free time, despite the complete and utter lack of rain this winter/spring, and started working on this saw again. Picked up an abandoned 550 (losing compression due to debris building up inside the cylinder/bearings; other possible issues as well as saw was incredibly dirty) for the tank handle and parts. Here's a write-up as of last use.
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2013 550xp Pawn Shop Project Saw
(Initial details/photos on arboristsite, "How Bad is This Piston?")
Serial Plate info:
s/n 2013 0600488
966 64 82-00
-- Purchased March 2019 in poor physical condition (acquired parts-saw in March 2020 and salvaged some things for the project-saw.) Hand cleaned and later blown out with air. Cakes of debris everywhere except internally; muffler had 1/4"+ layer. Air filter was fairly clean. Spark-screen was clean. Case seams still have some gasket material showing.
-- Two Punctures in original tank-handle; patching attempts failed, but may try again in the future.
1) small hole underneath
2) Sizable tear & puntcures in elbow/interior groove
-- Cylinder and piston aren't terrible. Dirty, but not badly scored. Bearings free of debris. Piston-rod coloration is good, no excess play. Piston and cylinder were lightly cleaned with 2-stroke and fabric. Piston-ring in decent enough shape.
-- Right brake handle bolt-housing stripped.
-- Sprocket was very worn. Near-new chain came with the saw. Some Mg missing from saw and clutch-cover. Chain catcher in bad shape; filed down some.
-- Bar was badly beaten, not square, with chips in the metal, heat spots, burrs, etc.
-- Clutch was on backwards and would not come off with clutch tool or various hand tools AND an additional set of hands. Shop was able to remove. Replaced with 2-spring shoe style clutch. New needle bearing and 3/8 small 7-pin sprocket used.
-- Flywheel and starter-cover were very dirty. Recoil missing parts but functional. Swapped covers.
-- Muffler gasket was deteriorated. Base-gasket starting to wear, but reusable for short term.
Events
2/15/2020 - Sanded and removed original tank-handle patch attempt. My first attempt was unsuccessful. Acquired spare plastic from a 357xp top cover (cleaned and degreased) and attempted to fill/re-mold but did not make a seal. Small hole patch also failed. Plastic cools/cures too quickly to be malleable.
3/14/2020 - Acquired parts saw and swapped tanks. Put back together (less muffler gasket) and idled for ~12 minutes. Ran rough/hard at first but settled out; hard to turn over on first start, but subsquent attempts fire on 2-3 pulls. For short term, base-gasket is okay but will need to be replaced if saw is usable. Will also re-inspect and clean piston/cylinder. No loctite used on any bolts at this time. Gasket maker used where needed.
3/21/2020 - Saw hooked up to software at shop. No error codes present. Stats weren't alarming in regards to overheats or leans/leaks. Carb passed self-test. Forgot to get print out and hours, etc. Muffler gasket installed/sealed.
4/20/2020 - 2+ tanks ran through. Attempted to allow idle to set, warmed up, attempted to set auto-tune. Mixed results. Saw began to wake up some on the second tank.
4/21/2020 - 2 tanks ran through. First tank was pretty good. Second tank was pretty rough, with noticable issues idling and restarting. Purge bulb cracked.
4/22/2020 - Saw started on first pull, first-stage of choke; then turned over on first pull on half-choke. Let idle for 11+ minutes. Made a few cuts,nothing prolonged, gave a few blips. Proceeded to set autotune noodling all 18" of bar into a fir log. Let idle/cool for ~30 seconds. Cut cookies on the opposite end of log, 3-4 at a time, running wide-open for up to 45 seconds, switching cutting direction each slice. Let cool ~30 seconds. Made another noodle cut ~45-50 seconds. Let idle for a few minutes. Repeated process with cookie cuts until near end of tank. Let idle until running out of gas, ~3:15 seconds.
Let saw cool for a few minutes, refueled, and started back on first pull (no purge). Let idle for 13 minutes, blipped a few times, shut off. Restarted and shut off a few times. Pull-cord "responds" easier/smoother like maybe there was drag. Let sit for 6 minutes to cool and started again, first pull. Should run another ~2 tanks through it tomorrow. Only annoyance is a split-second lag when pulling throttle while revving; make note of this.
*Note: If saw shows potential after 10-15 GOOD tanks, will do compression check on cylinder. May want to tear saw back down, re-clean piston/cylinder and add new base gasket. Consider disassembling and cleaning carb. Decide whether to swap air-filter assembly (for purge bulb) or delete the bulb.
4/23/2020 - At the end of first tank of the day, chain tossed. Went to put everything back together and the outer bar-stud popped loose into the oil tank. The one tank of fuel went well with good throttle response, revving, etc. There were a couple of times where it didn't want to start easily, but for the most part it was a good tank. Tank 5. Do not know when bar-stud will be repaired.