Stihl MS 290 re-build

[stubcut]

A friend of mine gave me a blown up 290 and I want to re-build it for the experience. I understand that I can fit it with a 290/310/390 cylinder. What little bit of reading I've done, the carb is different on a 390. I haven't read enough yet to see if the 290/310 has the same carb or the 310/390 has the same. Anyone got any info they can share here? Any and all help is useful. What are the best parts and where is the best to buy from?

 

[Ian_Hunt]

Here's a quick rundown:

MS 290: 46mm Piston
MS 310: 47mm
MS 390: 49mm

Carburetor is the same between 310 & 390, but 290 is different

Mufflers are different between 290 & 310/390, unless it's 2004 vintage or older, they were the same before then.

Oil pumps may be different, 290 had a lower output pump until 2004, now they are standardized.

290 is .325" pitch, 310/390 are 3/8" pitch, so you'd have to change over the sprocket.

Depending on the parts required (not including the ones required to figure out why it failed in the first place), you may be close the the price of a new saw.

Piston & Cylinder retails around $210 (+/-)
Carburetor retails around $40 (+/-)

A new MS 290 goes between $360 & $380, depending on bar length.

Buy parts from your local Stihl dealer, they are the only ones who can sell you originals.

Good luck!

 

[stubcut]

Thanks for the info. I've done some reading since I first posted this, some from over the net and some from some other forum sites. I tore into it and the exhaust side of the piston is scarred badly. I am trying to get out cheap, but if not I got a parts saw I suppose.

I suppose the way to tell the year model is by running the serial number? By what you're telling me this is need to know info.

 

[Ian_Hunt]

Sounds like a lean seizure, but would have to test to be sure. So you're looking at an air leak somewhere (crankshaft seals, cylinder gasket material, intake manifold, etc.) You've gotta diagnose and fix that, otherwise, you'll be wasting your money to repair.

You can find the approximate age by looking at the EPA sticker (silver sticker) on the rear handle - under the trigger. In the first line, it will say "M.D." or "D.O.M." (Date of Manufacture) with a month & year following like MM.YY.

My recommendation would be to buy another MS 290 and keep this one around for spares.

 

[stubcut]

Thanks again. I'll look it over good. I'll check the dates and such to see what I got. I've got other better saws so I doubt if I buy a replacement for this. I just thought it would be a cool project. I may have more questions later.

 

[oscar4883]

If the cylinder is able to be cleaned up you may be able to get away with a new piston. Like mentioned above, finding the reason it roached is key. Crank seals, for example, for that series of saw are pricey so it may not be worth it. Plus the cylinder is on the tricky side of things to install when compared to a pro saw.

 

[stubcut]

Thanks for the advice guys. My buddy at the saw shop looked this thing over and offered some tips. I was able to get a good used 310 cylinder and a new Stihl piston, both for around $100. I got her put back together and running. It wasn't really hard at all, great little learning project. Anyone got advice on the correct way to set the rings?

Overall a great day. I thought that I had blown up my 361 on Saturday, but tonight I messed with it and found that a guy helping us had put the chain back on incorrectly. It had the saw jammed up so bad that it felt like it was almost locked up. I didn't have time Saturday to mess with it. I put the chain back on correctly and she's back to normal. I love it when things come together like they should.

 

[Treetrim]

Muffler mod that takes 30mins from off to on and retune carb richer will give you faster cuts with 290 310 390. I got 23% from a 290 I tested. Didnt check 390 before and after but it was stronger and faster in the cut.

Muffler on these saws are choking them off.

 

[stubcut]

I did the muffler mod and got a buddy to put a tach on it to retune the carb. I can't believe the difference it has made on this thing.Giving it about two-thirds throttle in the cut, you can push it on down and it really picks up. I would have never believed it out of this thing. I didn't time it before so I've got nothing to gauge against. I've never run a 310 nor a 390, only the 290. This rebuilt saw has got alot more throttle response in the cut than any 290 I've ever used. It don't seem like it is running as hot either. I'm not ready to be a mechanic, but it makes me feel good to think that I've got around a buck 20 in it and my buddy was told it would cost more to fix it than to replace it.