Ms026 cheapish rebuild/fix

[Wonkydonkey]

so while looking on eBay, I came across a buy it now spares/repairs thing. A ms 026

https://www.ebay.co.uk/itm/stihl-ch...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

So I thinks and thinks, ohh stuff it, next I know I’ve brought it. So you never know what’s it’s like till it comes in the door and you open the the box.

So a few days later and I get it.
And yes it’s like the pics in the listing, no back cover and air filter, and no starter cover. The chain is 90% knackered but the 18” bar is ok.
So let’s look a little closer.
It looksy like some toss has been using it with the rakers way to high as the fine sawdust is all in the sprocket cover.
A quick check of the rakers reveals this . So next on the list is to look at the cylinder and piston

 

[fossil]

That cylinder looks like it would clean up. Certainly worth a try.

 

[Wonkydonkey]

The next thing was to practice masterminds cylinder clean up. And after reading &watching a few times, I was ready, to not fudge it up this time.


Well the time paid off, it took me about an hr, not knowing how far to go.

So all was done, now it was time to see if it would work ok. I had an old semi used 44mm piston and newish rings, I popped it on and then had to dismantle a ms260 for an exhaust and starter cover, I had a new air filter.
Time to put some fuel in and see if it runs.

A few pulls later, and no luck. So a few mls of fuel into the cylinder, and and she pops. A few more and she farts, a few more and away we go.

I try to do a quick rev and tune, I get it sounding about right, and then stick it in some wood.

Ahh chain is well duff, saw dust city.. I pops on a sharp 16” 325 and it rips,

I tried a few more cuts, then next I hear a lean reving sound, ummm, I tries a quick re tune. And a cut..... but it seems like something’s wrong... seals? We are talking a 20yr and more saw. I give it a turn from side to side. But I think i have an answer... try again to see if I,m correct, then I thinks.... no wait a min is it a vac in the tank, I release and pressure/vac, still no joy, I looked at the fuel filter, umm looks clean, almost new as does the fuel line.

Next stop is the carb strainer, ooeerrr look what I found.!
So all that funky saw dust found its way to the carb strainer, and the carb is a wt194 .. umm.

So I cleaned it out and run it I like I stole it. Yep. I guess that’s why it lean seized in the cut before. Fuel starvation.... so I’ve ordered some parts and will be getting it back together.

Although, on the timing side of things, (I will look at the pics I posted) I can see carbon in \half way into the transfers. Is this back stuffing ?

I’ve yet to time the ports.

 

[Wonkydonkey]

Yeh Tim @fossil it did and very well too..

So you can see in the first pic of the carbon half way into the trans.

So now to wait for parts from China and UK


Then the build will resume
As well as timing it to find out why there’s carbon in the trans.

Cheers

 

[fossil]

I fixed up an 036 with some parts from China (and some OEM stuff where it mattered).

It made the fix financially feasible and worked out very well.

 

[Wonkydonkey]

Yeh, same here, I just thought this could be a good project saw, you just never know what’s in the box till it’s opened, and then you still get some surprises when you pull it apart,

And in this box so far is a mahle 44mm which iirc, @drf256 says is good/best timing numbers on all the 026 cylinders,, ,? And a wt 194 carb.

So now I have to decide if I,m to split the case and replace bearings..... ummm I did flush out the crank with kerosene, yep I got sum grey aluminium stuff, prolly from the lean seize

How does Ali from a lean seize work with main bearings?

 

[fossil]

I've never seen that before. The one's I've come across were clean. If you can split the case it's worth doing. You don't want something unknown running up a transfer.

 

[Wonkydonkey]

I’ve got the jar of washings sitting in my shed, I will try and take a few pics tomorrow,.

And I will agree, I was suprised at what I saw, but remember who knows who done what to this saw.
Edit, I got it with no exhaust or air filter, and it was run making lots of sawdust. Look at the carb pic in the housing . Loads of sawdust.....

I,m Just observing all that I’ve seen. And commenting on it.
Cheers

 

[fossil]

Stick a little magnet in the washings and see if you come up with any steel. That can be a good indicator is something's up with a bearing (sometimes). The cylinder looks great. As far as the oil in the transfers, not unusual if he ran a really rich mix.

I'd do the seals as well. They do often fail on a saw not run for a long time shortly after running for a bit, at least they do on some of the older saws I've picked up.

Don't forget to check the impulse line for leaks if it's old.

I can't say I've seen a carb screen that plugged up.

I have an 026. Likely older than yours as there's no snorkle on my 194. It's 44 mm as well and is pretty fast. I think it's early as it has one of those useless tank vents with the screw in it that pisses fuel.
It certainly out cuts my friend's 260.

 

[drf256]

Yeh, same here, I just thought this could be a good project saw, you just never know what’s in the box till it’s opened, and then you still get some surprises when you pull it apart,

And in this box so far is a mahle 44mm which iirc, @drf256 says is good/best timing numbers on all the 026 cylinders,, ,? And a wt 194 carb.

So now I have to decide if I,m to split the case and replace bearings..... ummm I did flush out the crank with kerosene, yep I got sum grey aluminium stuff, prolly from the lean seize

How does Ali from a lean seize work with main bearings?

Timing pretty much the same on all. The KS (which I hate for porting) tend to have better numbers.

 

[Bigmac]

Stick a little magnet in the washings and see if you come up with any steel. That can be a good indicator is something's up with a bearing (sometimes). The cylinder looks great. As far as the oil in the transfers, not unusual if he ran a really rich mix.

I'd do the seals as well. They do often fail on a saw not run for a long time shortly after running for a bit, at least they do on some of the older saws I've picked up.

Don't forget to check the impulse line for leaks if it's old.

I can't say I've seen a carb screen that plugged up.

I have an 026. Likely older than yours as there's no snorkle on my 194. It's 44 mm as well and is pretty fast. I think it's early as it has one of those useless tank vents with the screw in it that pisses fuel.
It certainly out cuts my friend's 260.

Just as a side note, my dad had two saws that plugged the carb screen, both at the same time, I cleaned it up and they both ran great, well it happed again a tank after I fixed them! I had put brand new fuel filter on them at the same time, the fuel filter wasn’t plugged but the carb screen was! I found the problem, my dad had store his gas can next to his bandsaw and sawdust got into the gas can( no cap,on a little plastic can with a side load) I was surprised that the fine dust got past the oem filter!!

 

[jb-chainsaws]

The next thing was to practice masterminds cylinder clean up. And after reading &watching a few times, I was ready, to not fudge it up this time.
View attachment 123080

Well the time paid off, it took me about an hr, not knowing how far to go.

So all was done, now it was time to see if it would work ok. I had an old semi used 44mm piston and newish rings, I popped it on and then had to dismantle a ms260 for an exhaust and starter cover, I had a new air filter.
Time to put some fuel in and see if it runs.

A few pulls later, and no luck. So a few mls of fuel into the cylinder, and and she pops. A few more and she farts, a few more and away we go.

I try to do a quick rev and tune, I get it sounding about right, and then stick it in some wood.

Ahh chain is well duff, saw dust city.. I pops on a sharp 16” 325 and it rips,

I tried a few more cuts, then next I hear a lean reving sound, ummm, I tries a quick re tune. And a cut..... but it seems like something’s wrong... seals? We are talking a 20yr and more saw. I give it a turn from side to side. But I think i have an answer... try again to see if I,m correct, then I thinks.... no wait a min is it a vac in the tank, I release and pressure/vac, still no joy, I looked at the fuel filter, umm looks clean, almost new as does the fuel line.

Next stop is the carb strainer, ooeerrr look what I found.! View attachment 123080View attachment 123081View attachment 123082
So all that funky saw dust found its way to the carb strainer, and the carb is a wt194 .. umm.

So I cleaned it out and run it I like I stole it. Yep. I guess that’s why it lean seized in the cut before. Fuel starvation.... so I’ve ordered some parts and will be getting it back together.

Although, on the timing side of things, (I will look at the pics I posted) I can see carbon in \half way into the transfers. Is this back stuffing ?

I’ve yet to time the ports.

I change seals on saws like this as a matter of course now, gives me the opportunity to clean off all the baked on crud and it costs about 8 quid for genuine seals

 

[Wonkydonkey]

[/ATTACH]

That washings from the crank, I did use a magnet, but nothing was attracted
Yeh I will be fitting new seals, cheap insurance reall.
The bearings are still a bit of ??? Should I or not, I don’t really have the tools. I could try make and bodge it thing.. the pto side is the side that gets the abuse.

Anyhow a few more pics

This is the fuel tank vent atm.

 

[fossil]

If they roll smoothly and you can't manually feel radial play the bearings should be OK.

 

[Wonkydonkey]

When I put in the clean kerosene into the crank case, for the second time flush I rotated the crank for about 4mins, this was to flush the bearings.

Afterwards I rotated it again, it felt smooth, but I guess I will have another check when I pops the seals out

 

[jb-chainsaws]

When I put in the clean kerosene into the crank case, for the second time flush I rotated the crank for about 4mins, this was to flush the bearings.

Afterwards I rotated it again, it felt smooth, but I guess I will have another check when I pops the seals out

If youre wanting to do bearings post case halves up if it’s worth it in postage and I’ll do them for you, I can get bearings for you on trade account at cost too.

 

[Wonkydonkey]

Cheers for the offer Jb. Although I will wait till I’ve torn it apart abit more. It’s hard to tell when the clutch side is still attached.

 

[ABarrick]

Timing pretty much the same on all. The KS (which I hate for porting) tend to have better numbers.

What don't you like about the KS jug?

 

[drf256]

What don't you like about the KS jug?

Made of a much harder alloy and often have plating into the ports.

When I was cutting squish with a mandrel, they took twice as long. Now with a lathe, it’s just some annoying plating in some ports.

On an 026, the interface of the plating and the chamber are rougher. The KS have the plating right up to the band. On Mahle, the plating stops a few thou prior to the band. So when u cut with a mandrel, the Mahle factory edge of the plating is perfect, the KS gets jagged and rough.

 

[jb-chainsaws]

Made of a much harder alloy and often have plating into the ports.

When I was cutting squish with a mandrel, they took twice as long. Now with a lathe, it’s just some annoying plating in some ports.

On an 026, the interface of the plating and the chamber are rougher. The KS have the plating right up to the band. On Mahle, the plating stops a few thou prior to the band. So when u cut with a mandrel, the Mahle factory edge of the plating is perfect, the KS gets jagged and rough.

I always find the KS jugs a much lighter alloy than the Mahle too, but yeah the plating into the ports is a *b-word sometimes