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chainsaw nose sprocket help

Post in 'The Gear' started by salmonhunter, Jul 9, 2012.

  1. salmonhunter

    salmonhunter Burning Hunk

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    Well this year is my first time ever cutting wood and I have had the end sprocket get jammed up 4 times now since cutting about 4 cords of wood in the last couple of months. I always manage to get it unstuck but it usually takes me quit some time to clean out the wood chips that are jamming it. Just wondering if this is a common thing or am I doing something wrong maybee my chain is to tight or or something Im not sure. All i know is its frustrating and a big waste of time to go back to the truck and take off the chain to try and free up the sprocket. Any tips from you more experienced cutters would be helpful.

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  2. ScotO

    ScotO Guest

    couple of questions. Is your bar a machined Pro bar or is it a cheaper laminated bar? Second, do you maintain the sprocket oiler holes often? There should be a tiny pinhole on either side of the bar that you can inject grease into with a small sprocket grease gun. If the bar is a laminated bar, look to see if the laminations are starting to seperate out by the sprocket, if they are it may be time to change the bar. If you have a pro bar, it will have a removeable sprocket tip. If you are maintaining that sprocket and it is still getting stuck, it may be time to either consider replacing the sprocket nose or get a new bar.
  3. salmonhunter

    salmonhunter Burning Hunk

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    the saw is a stihl ms250 I dont think it has the hole to grease the nose sprocket . I do clean out the bar grove and the oiler holes every other time I go cutting. It doesnt jam every time I go out I would say it jams once per cord. should I try putting grease in the bar oiler hole that is near the motor? i figured that would make it harder for the bar oil to get to the end of the chain.
  4. ScotO

    ScotO Guest

    no, the way I am understanding your problem, it is out on the end of the bar, correct? if your bar does not have a small pinhole near the axle of the sprocket on the nose of the bar, you need to put some heavy oil down in the sprocket from time to time when you remove your chain from the bar. Then work the sprocket so the bearings in there get that heavy oil. Gear oil or something with a heavy viscosity would suffice. Do that every time you do a job and you should be OK.
  5. jeff_t

    jeff_t Minister of Fire

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    If it's getting jammed up with chips and sawdust, lubrication likely isn't the issue. It happens. Try to keep the rpms up until the chips have cleared. Don't let the chain stop in the cut. Hasn't happened to me in quite a while, but sometimes I've been able to free it up by catching a couple of teeth on the log and pulling backwards on the saw. If you can get the chain to move, a little throttle will clean it out.
    OldLumberKid likes this.
  6. bogydave

    bogydave Minister of Fire

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    Could be the chain is getting tight after you are running for a while. The bar may get hot, expand & the chain gets to tight.

    I do what jeff said, if I get a chips in the nose. Drag the teeth on the log so the chain goes a little backwards & then hit the throttle.
    At high RPM the nose sprocket should self clean.

    I dig what Scotty is saying, but my bar has pin holes on the nose to pump grease into the nose sprocket bearing. I don't think the 250 stock bar does.
    I clean the nose sprocket now & then, get the gunk out, spray in some WD, hit it with air & get it spinning easy by hand. I've hit it with the air hose & spun it fast a couple times too. Then I grease mine thru the pin holes. Some heavier oil dripped in there with your bar may help.

    It may be a chain oiler issue.
    Check your oil flow. You may need to adjust the chain oiler for more oil if that's a feature on your saw.
    Also the oil pump & tank can get dirt , wood chips in it when you add oil & block flow & it won't oil the chain properly. Drain the oil & clean the oil tank with diesel (gas if that's all you have) a few times.
    Push a wire in the holes on the bar that feed oil to the chain & make sure they are clean. I hit it with some air too.

    Found this (a feature of the new 250 bar), (there may be dirt in here):
    Ematic™ Bar includes a polymer ramp reservoir which holds bar oil until it can be picked up by passing chain.

    Let us know what you find out
  7. Jags

    Jags Moderate Moderator Staff Member

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    Does your oil consumption nearly match your fuel consumption? It typically will not go down as fast as the gas, but you should have the need to refill it with every tank of gas (in other words, you should not be able to run two tanks of gas to one tank of oil). If this is the case, then you have a lube problem.

    If it is a chip issue, you may be running your chain too looses. With the chain tight, you should be able to lift the chain in the middle of the bar, but not be able to lift high enough to see the bottom of the drive link. As said above, on occasion I will manually nose the bar into a log to get it to turn and then hit the throttle to clear the tip.

    Too tight and you could be creating heat that seizes up the chain.
    OldLumberKid likes this.
  8. salmonhunter

    salmonhunter Burning Hunk

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    Im 99% sure its from wood chips jamming the sprocket. Like I said It doesnt happen all the time but when it does it frustrating. Next time it happens il try dragging the teeth on a log and see if that helps. In the mean time Im gonna tighten the chain a little and see if it helps.
  9. jeff_t

    jeff_t Minister of Fire

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    Ya, keep the chain tight.

    Seems like when it happens to me, it's when the chain stops in the cut. Usually when I know it's time to pull it out, then I don't and it gets pinched. I'm a cut-part-way-through-and-roll-it guy, and usually know when to stop, but I still do it now and then.
  10. TimJ

    TimJ Minister of Fire

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    Sounds like your running a chipper chain and pushing it too hard. Let the chain do the cutting and quit bearing down on the saw
  11. OldLumberKid

    OldLumberKid Feeling the Heat

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    Not meaning to hijack the OP's thread, but I was having issues too, so I revived it
    as I thought it might help and for others who encounter this down the road.

    [​IMG][​IMG]Weird. I have been having recurring nose sprocket jams with the same saw -- MS 250 with a rollomatic—the bar has never really spit off oil even when new. Others have posted elsewhere the MS250 is stingy that way. It pumps alright without a bar/chain, but it doesn't take much to stop the lube flowing.

    Today I thought the sprocket was stuck for good, but managed to get it unjammed with some WD40, patience, and a piece of pristine bicycle brake/derailleur cable that really gets the crud out of the groove, etc.

    Things get hot quickly when the sprocket gets jammed though. It even ignited some noodles in the kerf — smoking when I got them out of the log, which means the bar/tip must have gotten hot.

    I've done a lot of cleaning on it the oil port area, I clean the bar with a toothbrush every time to keep it crud free, so I'm a bit mystified why it keeps happening so readily. Maybe operator error and not enough RPM's at critical parts of a cut?

    'll try the compressed air in the sprocket and see if there's a way I can lube it better before I begin next time.


    [​IMG]
  12. MasterMech

    MasterMech Guest

    You guys aren't the only one having this issue. My MS230 was doing the same thing last time out. I run it WOT in the cut, don't usually have the nose buried either.
    OldLumberKid likes this.
  13. ArsenalDon

    ArsenalDon Minister of Fire

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    I am actually wondering if you are getting enough bar chain oil going. My Husky does not want to throw enough oil so I use a mix of bar chain oil and 10W40 and this keeps things cooler and running right.
    OldLumberKid likes this.
  14. lukem

    lukem Minister of Fire

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    When is the last time you scraped out your bar groove? I scrape mine every time I have the bar off and am always surprised at how much goop comes out of there. I use a piece of wire pounded flat on one end, but a small flat head screw driver would work too. It could be that you are getting build up in there that is working its way down tot he sprocket.

    The other thing I've seen before is if your chain isn't sharpened evenly you'll start to get a sideways cut... \ instead of this |...and that can cause the top of the chain to ride up in the kerf leaving room for sawdust to get between the bar and chain.

    +1 on the drag backwards then WOT to clear the jam.
  15. OldLumberKid

    OldLumberKid Feeling the Heat

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    Agreed, I'm also pretty obsessive about cleanup after every use -- I take the bar off each timem and used to use a toothbrush, or bike cog/chain brush — now I use the wire in the picture below — yes it's amazing how much crud the wire will liberate from the groove.

    [​IMG]

    The bar chain is close to new and has not been sharpened yet -- less than a full cord cut with it.

    As for the odd cut -- yes, the recent time, I was trying to get two noodle cuts to meet from opposite ends, and afterward I noticed noodles building up in the kerf where the other cut had been, and as things ground to a halt in the groove.

    I really wonder if enough oil is getting to the sprocket area. I'll have to keep a much closer eye on it.

    I'm not sure if I've been to tentative with the throttle in the past, where a WOT might have helped avoid buildup. But that said, we have a few people having issues with the 250 being stingy with the oil.

    It rarely looks like it throws enough.
    Think I might check that out if it continues to be a problem.
  16. ArsenalDon

    ArsenalDon Minister of Fire

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    If your oil is turned up all the way then it just may be that the oil is too thick. When it is cold out the oil gets too thick to lubricate. Theoretically you can lube with only 10W40 but I cut mine to a 50/50 blend. It should throw oil pretty good.
    OldLumberKid, TreePointer and ScotO like this.
  17. ScotO

    ScotO Guest

    Zap and Smokinj use Canola oil, which would probably be a good oil to use on very cold temps. Give that thinner oil a try and see if it lubes better.

    In cold weather I keep the bar oil in a warm place (in the cab of the truck, for instance) and it oils alot better. When oil gets cold, it turns to jelly. Hard for that tiny oil pump to push jelly out of a 1/8" hole.......
    Tuneighty and OldLumberKid like this.
  18. lukem

    lukem Minister of Fire

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    Poor lube usually generates a lot of heat and that bar doesn't show any sign of getting the least bit hot. Still doesn't mean it isn't lubing enough.

    If you run the saw at WOT and hold the bar tip near some snow or a tree or something...is it visibly slinging lube?
    OldLumberKid likes this.
  19. OldLumberKid

    OldLumberKid Feeling the Heat

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    What you see there is a cleaned up bar after I got it unjammed.

    No, it doesn't sling. never has, not even when it was warm and new.

    I saw the pump pumping without the bar on so that was good.
    I do see some oil on the bar but never "slinging off."

    The saw stays indoors so it's coming outside at basement temp (about 40 F.)

    I clean the grooves and that reservoir thing. Gotta be some other hole that is plugged. I don't see any sprocket oiler holes that Hearth.com Members mentioned to the OP. I'll take a closer look.

    P.S. a few noodles stuck in the kerf started to smoke like kindling — musta got real hot for them to do that.
  20. Jack Fate

    Jack Fate Feeling the Heat

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    Just a thought , when my 192 was not oiling well I found a split oil line feeding the pump. Replaced both tubes , works good now .Oh & there is a strainer /filter on the intake tube (in oil tank) you could clean . Always keep the rpm's up .I try to make sure it's slinging good and that seems to clear things out .As long as it didn't get to bad.(impacked)
    Reminds me of the tires on my jeep .First I had mudders (self cleaning ) hated the ride ,like a paint shaker.So went to different tires (NON self cleaning) Went back to the guy who sold them to me & said hey they are better on road but get all caked up & loose traction badly .He ask me if I clean them out .
    WARNING BLONDE MOMENT ;em I say yes they were clean when I started .He states again you need to clean em out .So what I need to get out in the mud & physically scrap them or what? He says JUST SPIN THEM UP . So next time I'm in the mud I hit the throttle hard, mud flies all over (covers jeep) Jeep drops down & away I go ,COOL (except for clean up)

    The same applys to the saw
    but hey that bar needs oil to survive

    Good Luck
  21. WarmGuy

    WarmGuy Minister of Fire

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    This had never happened to me until the last two times I was cutting. I had just reversed the bar, and cleaned out the groove (which was already quite clean) before it happened. I had also checked that the oil was feeding properly by holding it near a stump while I accelerated the saw.

    I had never lubed the pinhole ports.

    The first time I needed to remove the chain and move the sprocket with a screwdriver before it cleared.

    The second time I just loosened the chain and was able to move it by hand, and it suddenly moved easily again.

    I was cutting newly felled Monterey pine.

    Could it be that I had the chain too tight?
  22. Jack Fate

    Jack Fate Feeling the Heat

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