In loving memory of Kenis D. Keathley 6/4/81 - 3/27/22 Loving father, husband, brother, friend and firewood hoarder Rest in peace, Dexterday

Uh......there's more.

Discussion in 'Chainsaws and Power Equipment' started by LordOfTheFlies, Mar 3, 2022.

  1. LordOfTheFlies

    LordOfTheFlies

    Joined:
    Apr 5, 2019
    Messages:
    2,519
    Likes Received:
    12,090
    Location:
    NY
    Got the rubber flappy thing for the fuel tank vent. When I went to take the old one out I found out why it wasn't working. :rofl: :lol:

    :doh:

    2022-04-08 16.09.01.jpg

    Put a 33RS114 full comp chain on it - 36" bar - and holy moly this saw is a BEAST. I felt like a video game character holding a massive minigun or something.

    Did some test cutting to make sure everything was running well and man it sure is running well. I can't wait for my buddy to see it.

    2022-04-08 16.41.16.jpg 2022-04-08 16.41.18.jpg
     
    Chaz, MikeInMa, M2theB and 2 others like this.
  2. LordOfTheFlies

    LordOfTheFlies

    Joined:
    Apr 5, 2019
    Messages:
    2,519
    Likes Received:
    12,090
    Location:
    NY
    Ok some bad news. The MS660 came back because my buddy said it wouldn't start. I tried starting it to no available. The spark plug was dry. Not flooded. I tried spraying some starting fluid. No go. Uh oh.

    And this is what I found when I pulled the muffler.

    2022-05-16 17.35.33.jpg 2022-05-16 17.45.34.jpg 2022-05-16 17.52.01.jpg 2022-05-16 17.52.05.jpg 2022-05-16 17.52.10.jpg 2022-05-16 17.52.17.jpg 2022-05-16 17.52.21.jpg 2022-05-16 17.52.25.jpg

    So as you can see there's massive scoring on the piston on the exhaust side. There is a tiny bit of scoring on the intake side, on the clutch side of the piston.

    The bolts for the cylinder were not loosey goosey but they were not as "tight" as I like. They had blue loctite on them.

    I don't think the saw was straight gassed...but my suspicion is that the saw was run hard without being properly warmed up. The reason I say that is I saw the my buddy's workers when they cut down a leaning cherry tree on my property and they didn't warm up the saws at all and it was the first job of the day in the morning.

    The scoring was so bad it scored the OEM cylinder that I had cleaned up the aluminum transfer on previously. But would that cause the scoring on the piston on the intake side?

    What do you think huskihl BuckthornBonnie MasterMech Chud M2theB ?

    This is the only saw that has come back to me and it has been about a month. Not sure how many times they used it. Details are a bit lacking.

    And to solve another mystery I think perhaps I put the MS460 muffler heat shield on the ms660. According to this IPL diagram there is no heat shield for the MS660??

    upload_2022-5-16_19-9-39.png upload_2022-5-16_19-10-35.png
     
    MikeInMa likes this.
  3. BuckthornBonnie

    BuckthornBonnie

    Joined:
    Oct 4, 2013
    Messages:
    963
    Likes Received:
    3,134
    Location:
    Penn Yan, NY
    Tough to say for sure (as with all pics), but probably a lean seizure. Lots of heat there… just need to find out why.
    Did you replace all rubber parts? Bearings? I can’t recall on this one.
    If you had aluminum transfer left in the cylinder, it usually scratches the piston early on and runs like chit.
    Is this the saw that was tough to start?
    I think everyone knows what I’d do… complete case split with new bearings and build it up right. The cylinder may still be salvageable.
     
    LordOfTheFlies likes this.
  4. Chud

    Chud

    Joined:
    Aug 15, 2020
    Messages:
    5,496
    Likes Received:
    37,374
    Location:
    NC
    The only thing I can add is that tree service saws don’t get warmed up. None that I have ever seen anyway. Fire it up and cut! A friend recently showed me pics of tree service saws that had 3 failures just like yours. They said they all happened while saws were cutting on their side.
    I agree that it’s good to warm a saw up before loading it, but it doesn’t happen in a work environment. I’ve only witnessed one Stihl meltdown in my life and I could here it was running lean before it let go. Good luck trouble shooting the cause.
     
  5. LordOfTheFlies

    LordOfTheFlies

    Joined:
    Apr 5, 2019
    Messages:
    2,519
    Likes Received:
    12,090
    Location:
    NY
    If the seals were shot then I would imagine it would have been near impossible to tune the saw and keep it running. Correct?

    I cleaned up the aluminum transfer on the cylinder walls and there was a tiny bit stuck in the corners of the exhaust port that I just couldn't reach.

    This is the saw that was tough to start - in that it hurt if you didn't push the decomp in - not that it wouldn't start. I've never started such a big azz saw before.

    And yeah, tree service workers really need a (stern) lesson in warming up the saws. I recently got in touch with my ex-boss and we started yapping about chainsaws and he said he has five. And I was like why the heck do you have five? And he said because he keeps running them.....and then one day they just won't start.......and then he just buys another one......and I asked him if he ever warmed up the saws......and the answer was a sheepish no.

    I did test the saw with the 32" bar and it felt fine....but I didn't test it for like 3 or 4 days....I only tested it the one day. Perhaps I should hold onto to saws for a few days going forward to make sure. I've noticed that when it gets humid or hot or cold out the saws tend to need a micro adjustment here and there....
     
    Chaz and MikeInMa like this.
  6. BuckthornBonnie

    BuckthornBonnie

    Joined:
    Oct 4, 2013
    Messages:
    963
    Likes Received:
    3,134
    Location:
    Penn Yan, NY
    The base gasket… maybe that was your air leak.
    Most stock 1122s run good for me under 13000 rpm. Anything on the fringe of lean can build up heat and run enough to score.
     
    LordOfTheFlies likes this.
  7. BuckthornBonnie

    BuckthornBonnie

    Joined:
    Oct 4, 2013
    Messages:
    963
    Likes Received:
    3,134
    Location:
    Penn Yan, NY
    Lots of debate on warming up air-cooled two strokes. I usually do just a bit, but nothing crazy.
     
    LordOfTheFlies likes this.
  8. LordOfTheFlies

    LordOfTheFlies

    Joined:
    Apr 5, 2019
    Messages:
    2,519
    Likes Received:
    12,090
    Location:
    NY
    I used 1184, let it "skin" up, below the gasket, and on the bottom of the cylinder. Should I not do that? I did not lay it on thick and was careful to wipe up any mess.

    It makes a lot of sense to me in that a piston will expand a lot quicker than the cylinder as there's more meat on the cylinder to dissipate heat. Overrevving/pushing a saw hard sounds like a possible cause too. I don't specifically remember in my mind whether or not I tightened the cylinder bolts....but I'd like to think that I always do. That said, I have forgotten to torque down lug nuts when swapping winter/summer wheels/tires so it's definitely also a possibility.

    How does warranty work on a situation like this?
     
    MikeInMa likes this.
  9. Chud

    Chud

    Joined:
    Aug 15, 2020
    Messages:
    5,496
    Likes Received:
    37,374
    Location:
    NC
    There are some guys that just have to turn carb screws too. After seeing some of your tree guys saws, there’s no telling.
     
    LordOfTheFlies likes this.
  10. LordOfTheFlies

    LordOfTheFlies

    Joined:
    Apr 5, 2019
    Messages:
    2,519
    Likes Received:
    12,090
    Location:
    NY
    I thought of that as well. Except this carb has those red nylon inserts and so you can't turn it much without removing them. And they are still intact and not easily removed.
     
  11. BuckthornBonnie

    BuckthornBonnie

    Joined:
    Oct 4, 2013
    Messages:
    963
    Likes Received:
    3,134
    Location:
    Penn Yan, NY
    Those are limiters and always gets pulled on older saws (out of warranty) that I work on.

    Did you tach the saw when you tuned it? Decent four stroke out of wood?

    Not warming up the saw did not cause that damage. Heat… and lots of it… did. I’ve seen many top end repairs fail on the forums because the real issue wasnt found. That’s why I go through every possible location an air leak can develop if the top end is fried.
     
    MikeInMa and LordOfTheFlies like this.
  12. BuckthornBonnie

    BuckthornBonnie

    Joined:
    Oct 4, 2013
    Messages:
    963
    Likes Received:
    3,134
    Location:
    Penn Yan, NY
    Warranty work on your end? Offer to look at it again but give him an honest labor rate including diagnosis. My gut instinct? Too lean due to an air leak that the limited carb couldn’t tune out. As always, I’d also question that bottom end.
     
    LordOfTheFlies likes this.
  13. brenndatomu

    brenndatomu

    Joined:
    May 29, 2015
    Messages:
    20,441
    Likes Received:
    127,196
    Location:
    NE Ohio
    Yup, that is more of a thing with liquid cooled...and even then most engines will still take some pretty severe abuse without cold seizing. I've seen air cooled bike motors go from cold start to instant bouncing off the rev limiter in every gear, no issues, still a dumb idea though, IMO.
    I still give my stuff a minute before any extended WOT...only ever blown up 1 engine...and it was just plumb wore out.
    Those pics look like classic lean seize to me...my 2 ¢
     
    BuckthornBonnie likes this.
  14. LordOfTheFlies

    LordOfTheFlies

    Joined:
    Apr 5, 2019
    Messages:
    2,519
    Likes Received:
    12,090
    Location:
    NY
    I did use the tach but I didn't write down the exact number and now I don't recall exactly what it was. I know it wasn't past 13000 on the high side but I will up my documentation game and write down the settings inbound and outbound. The carb was opened up about 1/2 turn out on the limited H screw when it was brought back to me. I'm also going to record a video of each saw before I take it apart just so I can document what the saw came with (or didn't come with), bar length, etc.

    Seems like a lot of people have burned up the 066/ms660. This guy burned 2 saws in 2 days!

    Cooked two MS660s in two days! in Chainsaws

    Based on that thread I'm going to turn the H jet all the way out.
     
    Chaz, MikeInMa and Chud like this.
  15. MasterMech

    MasterMech The Mechanical Moderator

    Joined:
    Oct 2, 2013
    Messages:
    9,523
    Likes Received:
    25,467
    Location:
    Greenville County SC
    Food for thought gentlemen.

    New saws are sold everyday to all kinds of operators. They go into service receiving no guarantee of proper care and feeding. As enthusiasts, we make sure we have clean bar oil in the reservoir, fuel up with perfectly measured fuel mixes (probably mixed a little heavier than 50:1), fit a freshly sharpened chain, and we relish in the process of firing up the saw, checking the tune, perhaps making a small adjustment to the carb settings, and then setting off to work. Heck, we even enjoy spending a few minutes (hours?) cleaning up a saw when the work is done. Only a slim majority of saws enjoy this pampering. The VAST majority of saws ride around in the back of a pickup, perhaps in a somewhat weatherproof box if they're lucky, get fed fuel mixed in a hurry at the gas station, oil from whatever bottles are in the back of said pickup, and certainly have never seen anyone spend a minute cleaning up the machine at the end of the day. Warm up a saw before cutting? :rofl: :lol: Some operators are so angry at the saw just for existing they are praying for it to melt down just so they can go back to scrolling Instagram. And yet these machines survive many, many hours of this type of use. Even the lessor "homeowner" models.

    Point is: these aren't Formula 1 engines. Built to tolerances barely measurable. Co-efficient of expansion carefully calculated and cross-checked to ensure every single component is at the optimal dimension once engine temperatures stabilize. Nope, these units are intended to go to work in the hands of an operator that may or may not understand what a micrometer is and how it's used. Their goal is to make one piece of wood, more than one piece of wood, and the saw is a tool that, hopefully, is the easiest way to get that done.

    Not warming up that saw before cutting didn't kill it. Something was wrong when it left, went wrong after it left, or it was sheer operator neglect/error that killed it. If that piston was clean on top when it left, it ran for awhile before failing. Long enough to cover the top with carbon again.

    Also: I don't use anything on most base gaskets. These saws left the factory assembled with dry gaskets and ran for years like that with no issue.
     
  16. Chud

    Chud

    Joined:
    Aug 15, 2020
    Messages:
    5,496
    Likes Received:
    37,374
    Location:
    NC
    Even the lessor "homeowner" models.
    Aka XP’s :rofl: :lol:
     
    LordOfTheFlies likes this.
  17. Canadian border VT

    Canadian border VT

    Joined:
    Feb 18, 2015
    Messages:
    16,821
    Likes Received:
    108,920
    Location:
    Vermont
    Great thread, I am just following along..
     
    LordOfTheFlies and MikeInMa like this.
  18. LordOfTheFlies

    LordOfTheFlies

    Joined:
    Apr 5, 2019
    Messages:
    2,519
    Likes Received:
    12,090
    Location:
    NY
    Nice summary. Thank you. Makes a lot of sense to me.

    The piston was brand new so yeah I noticed the top covered in carbon as well and thought the same thing.

    I'm working with the crew today to help out my buddy since he's out with what appears to be Covid. I'll be asking them what went wrong and hopefully they can shed some insight on what happened. l
     
    MikeInMa likes this.
  19. MasterMech

    MasterMech The Mechanical Moderator

    Joined:
    Oct 2, 2013
    Messages:
    9,523
    Likes Received:
    25,467
    Location:
    Greenville County SC
    I was thinking of the "disposable" MS250's that were handed out like breath mints to ground crews. Most of them survived! :rofl: :lol:
     
  20. LordOfTheFlies

    LordOfTheFlies

    Joined:
    Apr 5, 2019
    Messages:
    2,519
    Likes Received:
    12,090
    Location:
    NY
    I worked with the crew for a day and they were "complaining" that the two 395xp they had were cutting crooked. When I looked at the chain one side of the teeth were noticeably longer than the other. However, the second I was handed the saw and did a test cut I could feel that it was loosey goosey all over the place.

    Well, here is the list of issues I ended up finding with that saw:

    1. Every single bolt for the anti-vibe springs was loose. Hence the loosey goosey-ness of the saw

    2. Missing anti-vibe rubber bushing at the tip of the handle (side closest to the tip of the bar)

    3. Ignition switch not shutting off saw. This turned out to be interesting - not only was the blue wire from the switch to the coil broken, but the ground screw on the black wire was also loose....So after swapping out the wire with a good one from a donor, it still didn't work! Then I realized the ground screw issue and put a dab of loctite on that as well. The multimeter was super handy here. Using it to test continuity is so useful.

    4. Case cracked right at the trigger assembly on both sides of the throttle. Not a problem in and of itself but this caused the spring to pop out of the place...which caused the throttle to feel very wonky - the travel was shorter and not smooth at all. Fixed this by popping the spring back into place.

    5. Trigger was not pulling the carb to WOT completely. There was a gap. So I tried huskihl's suggestion on another side of rotation the carb but that didn't help. I also tried replacing the wire because I thought it had stretched so I took a good wire from a donor saw....but that didn't help EITHER. I didn't have thin wire so I ended up just using a zip tie right at the end of the throttle cable and luckily it works perfectly. So now the saw is putting out 100% of its capability. I had cleaned the carb area and blew it out. There was a ton of debris there.

    6. The right rubber carb mount was ripped in half and just dangling. I was able to swap that out from a donor saw as well.

    7. All screws for the wrap handle were also loose.

    8. Made sure the tach was under 12,500 rpm. I adjusted the H screw to a final rpm of 12,100.

    9. Put in a new spark plug, blew out the air filter, washed all the covers (flywheel, spark plug, top cover, clutch cover) and cleaned out the clutch drum, cleaned and lubed the clutch needle bearing with some white lithium grease.

    10. On a side note I drove to his lot and replaced the driver seat plastic trim for his Ford F-150. Also pumped up his front tires to 40psi to match his rears. His fronts were at like 25 and showed significant outer edge wear indicating he had been riding on low pressure for a long time.

    Cracked handle.

    2022-05-19 15.12.53.jpg

    Broken carb mount

    2022-05-20 12.19.13.jpg 2022-05-20 12.24.13.jpg
    2022-05-20 12.31.51.jpg

    Donor saw on right

    2022-05-20 12.31.47.jpg

    This is how I fished the new throttle cable wire by zip tying both ends to each other without having to remove the handle from the crankcase.

    2022-05-20 13.02.04.jpg

    Carb WOT throttle fix with the zip tie.

    2022-05-20 13.26.21.jpg 2022-05-20 13.28.53.jpg 2022-05-20 15.22.28.jpg 2022-05-20 15.33.14.jpg