New (to me) Stihl MS260 - few questions

[aesmith]

Hi,
So as you might guess from the subject I've picked up a used MS260. It's not branded "pro" but has decompression valve, adjustable oil pump and carb with both H and L screws.

As far as I can see everything works OK but some of the works were a bit gummed up. I've cleaned the brake mechanism, air filter, starter, and removed most of the grot in other spaces. The only issues I've found so far are a worn starter cord and sprocket. The saw starts, idles and revs OK, oil pump works. No oil or fuel leaks when I leave the saw standing. The spark plug was quite black making me think it's running a bit rich. I've not touched the carb.

I've already picked up a genuine Stihl rim sprocket kit, an SKF (not Stihl) needle bearing, and I'll fit a new plug as well.

Apart from welcoming any general comments or advice, I would appreciate comments on the following ...

(1) Are there are any parts that you'd recommend replacing as a matter of course on a used saw where you don't know the history? I wondered about brake and clutch springs but they seem fine (I had to replace the clutch springs on my last saw as it tended to run the chain a bit when idling - this one doesn't do that.)

(2) When replacing parts, are there any areas in particular where you'd advise steering clear of third party or Chinese parts, and using only genuine Stihl?

(3) I need a new bar and chain. Existing worn one is .325, is there any benefit to using 3/8" low profile if I'm using a fairly short bar? Assuming that's possible.

Assuming I get everything running nicely, I think I'd like to open up the muffler a bit, but I'll need to post photos to get some advice on that. The fitted muffler doesn't look like the examples I've seen here.

Thanks in advance, Tony S

 

[cuinrearview]

1) If everything works, I'd take it to the woods and this question should answer itself after a few tanks.

2) The only Chinese parts I use are bar nuts, decompression plugs, and intake clamps. Even then, you can't ever count on what you get from the Chinese to be consistent. I would advise OEM for everything on a nice saw like that.

3) The advantage is less cutters, so less drag on the engine. As long as you're planning on running a 16" or 18" bar, it should operate just fine with .325 pitch chain. Focus your effort on keeping it sharp.

 

[John Lyngdal]

My first go to saw out of the dozens I own is a MS260 with a 16" .325 bar and chain with a 8 pin rim.
Keep the chain sharp and it will serve you well.

 

[PA Dan]

Here's what I do on a used saw with unknown history. I replace the fuel line and filter, impulse line and order a carb kit. These things are often over looked and I like to know they are new.

The 260 muffler is very simple to mod and would be the next thing on the list.

I love .325 .063 16" on my stock 50 cc saws.

 

[ericm979]

Check the spark arrestor screen and clean it if it needs it. Check the clutch drum for wear. The shop manual says what the spec is. You can request one on the 'beg for manuals' thread in the stickies area.

Take the muffler off and look at the piston skirt for wear. Also the amount of carbon on the part of the crown that you can see through the port.

 

[aesmith]

Thanks everyone. The clutch drum is getting replaced as I'm changing to a rim sprocket setup. The old spur sprocket was well worn. There's no spark screen in the muffler, I'll see if I can take a couple of pictures and see what you guys think about modding it. It looks very restricted at the moment. I've downloaded the user manual, service manual and parts list. I think I'll have a look to see prices for fuel, oil and impulse lines - some of the Stihl parts are surprisingly inexpensive if ordered from a trade place, but they have carriage charges and minimum order that makes it inefficient ordering just a couple of items.

 

[dmb2613]

run it , some will have you overhauling it befor you cut with it

 

[president]

the clutch side oil seal are known to go
making the saw run rev high,and run lean
they are hard to remove without the (seal
puller)from STIHL or aftermarket rig
great little saw ,it will serve you well

 

[sbhooper]

I would run it first, and then decide if there is something wrong. I have used the heck out of my 260, over the years, and he only thing that I did to it, is a muffler mod. Stay with .325/16-inch.

 

[atpchas]

I've never been keen on the 026/260 air filters. Be sure to keep 'em clean and if you need a replacement, go OEM. I've not yet seen an after market AF that I'd trust.

 

[aesmith]

Muffler pictures. There are two small scoops as outlets on the bar side above the engine casing. It would be tight to add more below them as there isn't much room between muffler and casing. Not sure whether it would be best to add additional outlets, and if so where to put them. Or open up the existing outlets in some way.

Inside there's a sort of box which has six holes each of around 4mm on the flywheel side (opposite the external outlets), and another six facing down. I would think the best option would be to open up those holes, or maybe cut slots between some of them. However I'm not sure if I'll be able to get any sort of tool into that location either from the front or from the back.

Finally what sort of total opening am I looking for, something like twice the orginal area?

 

[drf255]

Differences exist between European models and US models. That looks like an AM or 024 muffler to me. At least on this side of the pond 026 mufflers have no baffle and a front heat shield. I’d make a 1/2” hole on the flywheel side of the muff can, add a deflector in a spot that doesn’t hit the brake or case, and remove that inner baffle.

 

[aesmith]

Hi, hope it's OK bumping this thread with a couple of follow on questions. So I've now had a good look around the saw and I'm pretty happy with what I see. Piston looks perfect when viewed through the exhaust port. I've sharpened the chain and fitted the new spine sprocket kit and a new needle bearing while I was at it. The saw starts and runs and idles fine with no sign of the clutch dragging until its revved up. I don't have the gear to carry out pressure or vacuum test, or compression. However it runs and cuts well, which is the main thing.

One niggle, it seems slow to rev up from idle. It doesn't hesitate or cut out, the revs just rise slower than I'd expect, taking maybe 3 seconds to reach peak. Is that normal, or does it indicates something out of adjustment? The carb as both H and L screws and the limiters must have been removed by a previous owner. I thought I'd ask on here before tinkering with them.

Thanks, Tony S

 

[cuinrearview]

Give the L screw an 1/8th to 1/4 turn counterclockwise (more fuel) and see if that helps. You may have to turn the idle up a little.