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Rebuilding a Stihl MS290

Discussion in 'Chainsaw' started by babzog, Jan 7, 2012.

  1. babzog

    babzog ArboristSite Lurker

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    I inherited a 290 from my BIL when he closed his shop last year. Customer brought it to him in pieces in a recycle bin, needing a p&c. He was gonna pitch it but I saved it, figuring it would be a fun project. Picked up the parts and cleaned everything up today. Problem is, I'm not really sure where to start as I have no frame of reference to work by, not having torn it down and never having rebuilt one before. I'm not totally stupid as I used to rebuild model airplane engines as a kid but there's more stuff and parts on this and some I have no idea what they are or where they go.

    Was thinking I'd get started and ask questions as I go. I'll post pics as I progress.

    Will use 2cycle oil as assembly lube inside the motor.

    I figure I'll start by replacing the piston, then load that into the cylinder. Next, drop that into the lower crank case which is still bolted into the plastic case.

    I don't have special tools to deal with the rings - any tricks to doing it, poor-boy style?

    The bottom part of the crank case looked like it had a silicon type gasket as there was a piled of goo I brushed off (also looks like the same goo was on the crank bearings). Is there a gasket I can get from the dealer or should I just use some permatex?

    Anything I'm missing in order to get to this point?

    Where I'm starting from. I'm sure there is missing hardware (some parts are buried in this pic).

    View attachment 215784
     
    Last edited: Jan 7, 2012
  2. StihlyinEly

    StihlyinEly Addicted to ArboristSite

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    First of all, go to "The Beg for Manuals Thread" and request a shop manual (not owner's manual) and IPL. Someone will zap the electronic versions to you, and that will help a lot.

    You may have the weather a little contempt from a few 290-haters here, but someone who has rebuilt them (and there are quite a few folks here who have), will step in and give you a hand.

    Have fun with the project! :)
     
  3. babzog

    babzog ArboristSite Lurker

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    Thanks for the suggestion. What is an IPL?

    Edit: nevermind, saw the def when I went to the thread. :)
     
    Last edited: Jan 7, 2012
  4. jus2fat

    jus2fat Two Harley Fatboys

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    Thall..aka.."The King" did a step by step photo shoot of how to do it right.

    Was entitled 'One man's junk another man's treasure"...can't find it using search.

    Maybe someone else can find it and do a link..!!
    :cheers:
    J2F
     
  5. Stihl-Pioneer

    Stihl-Pioneer Addicted to ArboristSite

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    Here it is
    http://www.arboristsite.com/chainsaw/133453.htm
     
  6. babzog

    babzog ArboristSite Lurker

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  7. Saw Dr.

    Saw Dr. Junk Collector

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    There are several 290 rebuild threads. HERE is one I got in on. Another coming soon. I have my annual eval at work next weekend, and then I get to go back to the shop for playtime.
     
  8. dargo

    dargo ArboristSite Lurker

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    Look online..I just downloaded one after 5 minutes of looking.
     
  9. sefh3

    sefh3 Addicted to ArboristSite

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    No tricks needed to install the rings. I use a small flathead screwdriver to install them. Look at Saw Dr's post.

    I use Yamabond or Dirko for the sealant.

    The last one I rebuilt I bought the seals, piston, rings, and fuel line from Northwood Saws.
     
  10. cutforfun

    cutforfun Addicted to ArboristSite

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    you prob got a manual , but pull the bar stud and get the bottom of the motor out of the saw and your life will be much better.
    put the cylinder in a vice and drop the piston down into it. it makes it so much easier to see what you are doing(no tools required just us plenty of oil.
     
  11. babzog

    babzog ArboristSite Lurker

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    How do I go about pulling the stud?
     
  12. cutforfun

    cutforfun Addicted to ArboristSite

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    I take two bar nuts and thread them both on the stud then tighten them up against each other. Then you can put a wrench on the back nut and turn it out. make sure you get the second nut on far enough that it gets good bite or you can strip things out.
    It is not a must to pull the bottom pan but it is alot easier to get it put back together with out getting dirko all over everything. make sure you dont get the piston spun around when putting it in, i always get turned around a bit when its upside down
     
    Last edited: Jan 8, 2012
  13. dargo

    dargo ArboristSite Lurker

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    I just downloaded the repair manaul from STIHL. I have no idea how to post but look on google; takes 3 to 5 minutes.
     
  14. Danno

    Danno ArboristSite Operative

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    Welcome to the AS, Babzog! These guys will take good care of you, buddy! If I can help in any way, just PM me here or on hearth...
     
  15. Saw Dr.

    Saw Dr. Junk Collector

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    Read the linked thread. You do not need to pull (and likely ruin) the stud. Assemble the piston and crank into the jug, and then install that whole assy into the bottom pan/cradle assy. You have to turn the crank cheeks up, but it WILL go in there just fine.
     
  16. babzog

    babzog ArboristSite Lurker

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    Welp, the saw is together. I took some pics, but nothing you've not already seen in the two threads.

    I'd started it the week I originally posted and finished it up later the same week... just been tardy getting an update posted.

    Started in on it Sunday, got the piston pulled off and the new one on. There was an arrow cast into the top of the piston. Not knowing what else to do, I oriented it in the direction of exhaust flow. Carefully got the piston into the cylinder.. once the last ring was nudged into place, it just dropped in. The dealer only had one oil seal on hand so that was as far as I got.

    Picked up a new seal from another dealer Mon but had no time to mess with it. Tue, I got the new seal on, permatex on the engine and the halves mated. I should have run the bolts through the new block first because they were a sob to get on. I was worried I might have messed up the seal as the permatex was drying and the halves kept separating as I was getting the bolts in. Got it together okay. Left to cure.

    Wed night, I tightened down the bolts (just a 1/8 - 1/4 turn - no torque wrench at my disposal) and got the rest of the saw put together. Not too hard, though fiddling with the fuel and impulse lines and the wires in a space scarcely big enough for an gnat to crap in did elicit a few choice words. Impulse line kept popping off because the new nipple lacked the barbs to help lock it in place. Next day, I had my local saw shop dress/true the bar and grind the chain. Oh, and I needed a nut for the flywheel - one of two parts (the other being a bar nut) missing from the recycle bin of parts I'd acquired!

    Fired it up Thu night and she started after 6 pulls. Will take some break in time to let it run smoother (it bogs a bit when I give it the gas) but it idles nicely.

    Only problem is, the oiler is not working. It's pumping oil but it's not getting to the bar, spraying all around inside the sprocket cover. The oil holes in the bar are clear.

    Got the pin out - wear eye protection when you pry out those clips, they will fly!
    [​IMG]

    Getting the new clips in was a bit of a pita.
    [​IMG]

    But after diddling with it for a few minutes, it went in. Got the rings oiled and installed.
    [​IMG]

    Gently worked the piston into the cyl.
    [​IMG]

    New oil seals, oiled and installed.
    [​IMG]

    Magic happened and I wound up with this! Okay, so it's not magic, but from here on, it's just bolting it back together and the threads referenced above already show everything. Forgive the Poulan scabbard, it's what I had on hand and it fits this saw better than my 357XP.
    [​IMG]

    Thanks for the thoughts and links and such! Those were super-helpful! There were parts (ie: the little plastic thingy with the wire on it) that I had no idea what they were for. The photos in those links showed exactly where everything went. Helps a lot to have a visual reference when you don't disassemble and thus know where all the little bits came from.

    Saw: Free
    P&C: $65USD
    Oil seals: $16.45 x 2
    Fuel filter: ?? (I forget, wasn't much)
    Spark plug: $5
    Bar nut: $2

    P&C I got off eBay, the rest from local dealers.
     
    Last edited: Jan 31, 2012
  17. Danno

    Danno ArboristSite Operative

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    that was a heck of a bargain! Good job Babzog!
     
  18. Dan_IN_MN

    Dan_IN_MN Addicted to ArboristSite

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    Great Job!
     
  19. Fish

    Fish Account Hold

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    That bar scabbard is probably what burnt the saw up the first time!!!
     
  20. babzog

    babzog ArboristSite Lurker

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    Finally got an opportunity to give the saw a bit of a workout today. Ran a more oiled tank through just goosing the throttle as a break in, then another tank of normal 50:1 and letting her rip. I see what folks say about it being a bit underpowered. Though it has similar displacement to my 357xp, it can't hold a candle to it for speed. Easy to bog it down. Will have to keep a sharp chain and just let the weight do the cutting. I intend to use it as a backup saw anyway but I thought it would be a little closer to the Husqv, performance wise.

    I noticed one annoyance with it though. It win't idle very long. The rpm will slowly fall off till it dies. Any thoughts?
     
    Last edited: Feb 11, 2012

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