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Ms 362 sounds wrong

Discussion in 'Chainsaw' started by MervMaster, Mar 14, 2019.

  1. MervMaster

    MervMaster ArboristSite Operative

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    at work we have an ms 362. It wouldn’t start and sounded bad on pulling- scraping, rough pull etc. pulled the piston and cylinder, found scoring, replaced both with stens set for this saw.

    Carb is spotless, everything seems to be in order, but even with the new set up, it doesn’t sound right. A little “clack” sort of sound at tdc. It starts and idles for a second then quits and won’t restart.

    I believe crank seals are my only thing left unless someone has another idea. Is a leak down test the only way to proceed?


    Thanks in advance.
     
  2. Sam R

    Sam R 8mm Socket

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    A leak down test won't really tell you anything. What you need to do is a pressure & vacuum test of the crankcase. How was your other hardware, rod bearing, crankshaft, connecting rod, bearings?
    Also has the original cause of the scoring been determined?
     
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  3. pioneerguy600

    pioneerguy600 Lost in Space Staff Member

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    Check the air gap between the flywheel and module/coil frame, the gap is much tighter as the flywheel magnets approach the module. Seen many that the flywheel magnet was scraping the module if the gap is too tight.
     
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  4. MervMaster

    MervMaster ArboristSite Operative

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    The coil is definitely spaced right, all the other hardware seems clean. The saw got blown up before I got the job but our motor pool mechanic swears that a guy who retired could start it up no trouble with “no choke, no decomp, two pulls.” I don’t believe him as he likes to tell stories.


    The crank shaft does move stiffly when I have the cylinder off, it takes a little effort to get the piston in a good position.

    Can I make gaskets out of rubber for the vacuum test?
     
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  5. pioneerguy600

    pioneerguy600 Lost in Space Staff Member

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    An air leak will not make any mechanical noise but will cause a high idle condition and usually causes a more difficult start condition, re more pulls over than usual to get started. The 362 is more difficult to seal up due to the two intake ports, Gorilla tape will seal the intake side, rubber will seal the exhaust
     
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  6. MervMaster

    MervMaster ArboristSite Operative

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    Couldn’t say what the initial cause of scoring was. The whole thing is really clean and solid aside from the scoring.

    Is the crank shaft supposed to move free and easy? I find it to be a bit stiff.
     
  7. Sam R

    Sam R 8mm Socket

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    It should be able to move up & down pretty easily. One thing you can do as a cursory check of bearings is grab the very tip of the crankshaft (such as the flywheel nut) and while holding the saw down, try and move the shaft around. If there's any noticeable play in it, chances are your bearings are toast.
     
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  8. alexcagle

    alexcagle Cutoff Saw Specialist

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    Did you do a base gasket delete by chance ?
    I've seen some real turd Chinese cylinder assemblies come from Stens.
    I had a "Hencho en China" TS700 once, that I checked the ceiling squish, and ended up having to use doubled up metal cylinder base gaskets and yamabond #4, to get above .020" clearance.
    If you put the incorrect spark plug in, it can contact el pistoño.....
     
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  9. MervMaster

    MervMaster ArboristSite Operative

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    now that’s interesting


    The gasket is in place appropriately, but I did have to pull the jug back off once because I heard a little clank at tdc and when I pulled the plug off the clank went away. I disassembled and reassembled, changing nothing, put the plug in and no more clank.

    Still get the Weird sound as it turns over though.
     
  10. rd35

    rd35 Just an average Joe's brother!!

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    Sometimes on a real bad piston meltdown, the crank bearings will load up with aluminum particles and get stiff...bad thing is this usually destroys the bearings. Had this happen on a 310 I rebuilt for a guy who had straight-gasses his saw. Piston was badly eaten away. The crank bearings were not loose, but were very stiff with a lot of drag (hard to rotate them). I removed the bearings and washed them in solvent. Turned the solvent completely black as all that aluminum came out of the bearings. After cleaning, the bearings were loose and very rough...but rotated easy.....just felt horrible. They also made a loud clunk sound when they hit the bottom of the scrap metal bin!!!! Rod bearing was toast too after cleaning. So, this guy got a brand engine block assembly complete.
     
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  11. alexcagle

    alexcagle Cutoff Saw Specialist

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    You need to figure out what the noise is.
    Chances are, it's going to get worse.

    I've seen small bits of broken rings and debris get trapped in between the cranks and crankcase bearings before.

    I've seen Chinese pistons' skirts contact the counterweights of cranks before from lack of quality control, or a missed step in machining.
     
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  12. Sam R

    Sam R 8mm Socket

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    I have a feeling one or more bearings on your saw are not operating correctly.
     
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  13. Wood Doctor

    Wood Doctor Edwin

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    Believe it or not, I ran into this same problem with a Stihl Blower Vac engine. At TDC it clanks, will start, will not idle, and then shuts down. The difference, of course, is that MervMaster's saw is worth over $800 new and this blower vac can be replaced entirely for $180.

    What I am learning here (and what I also suspected) is that replacing the top end may not solve anything. The blower vac engine also seems to have good compression. I told the dealer about it and he said, "Scrap it." No encouragement at all.
     
  14. cary911

    cary911 ArboristSite Guru

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    Stihls just sound cheesy, period. … sorry, don't mind me. bored.
     
  15. MervMaster

    MervMaster ArboristSite Operative

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    No wobble in the bearings though. I’m starting to get frustrated. Maybe I’ll buy bearings and do it. Then at least I’ll know.
     
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  16. Wood Doctor

    Wood Doctor Edwin

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    One other possibility. The crankshaft needle bearing may have to be replaced. If there is play there, your new top end would not reveal that. It doesn't take much to set this off. But, I tend to doubt that failure. I seldom replace one unless the kit comes with it.

    I hate "squeaky spring" problems like this, especially when it's almost a new engine by chain saw standards. I doubt that you have the same 500 hours on your saw that I have on my MS361.
     
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  17. pioneerguy600

    pioneerguy600 Lost in Space Staff Member

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    The clutch drum?
     
  18. MervMaster

    MervMaster ArboristSite Operative

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    I hate these too. This saw has been around the shop a while but I doubt seriously if it’s seen 40 hours. We have others to use when we need to, and my understanding is that this one has been trouble for a good while before it failed entirely.


    If I ever get it going I’ll post the results.
     
  19. drf255

    drf255 BAD CAD

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    Remove all the parts you can from the crank outer, then inspect the seals and rotation effort. It should spin totally freely.

    I missed the part where you diagnosed the original failure of the P&C. Way too many times we see someone replace a top end, only to score the next one. A scored top end is generally a symptom and not a cause for a problem.

    Don’t toss your OEM top end. You may be able to restore it. Add a meteor piston and it will give you many more years of work and better performance than the China one you bought off of Stens.

    For the life of me, I don’t know why I will get an occasional “clank” sound when the piston changes direction at TDC and nothing is hitting it. All the bearings are tight too, and the saws run just fine.
     

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