MS261 M-Tronic Build

[spudulike]

You can use a smear of liquid gasket to sort that out but have seen screwdriver damage around the end of the manifolds where the uninitiated lever the manifold out of the back of the air box and slip. Easy to miss if you plug the manifold to seal it.

....the joys

[Heavy Oil Saw]

I’ve had a look at the rubber inlet manifold, and there’s no sign of damage, but I’ll try and leak test it. Use the carb on the plastic carb mount (has the two threaded bars) and slide in a slither of rubber between the carb and manifold, then tighten all down, and see if it works.
I keep forgetting to put the metal washer in when I assembly it though.

[Heavy Oil Saw]

Glad it is looking good though, always an important test as if you get any weird running, you know the main engine is 100% sound and the issue must be somewhere else.

On this note, I’ve ordered a carb kit. Don’t like dealing with carbs, but thought what the hell, got it apart and the diaphragm is nasty hard, and that area had plenty of saw dust build up, well more than I thought should be there, and I’m no expert.
There’s a “strainer” in the carb, judging by the parts diagram, but was missing when I opened it up? Is this a mod or some other reason to be deleted unbeknown to me?
The carb will be flushed through with cleaner, and left to dry. Hope this alleviates any fuelling problems. I flushed the carb when I had the solenoid out to replace it, so maybe I back flushed the crud into the diaphragm?
Going to run this thing on premix fuel, so do it now, and save the hassle later.

[htb]

Replace the gauze strainer filter, as least a new one will be clean. A used one often looks clean, but when held up to the light they often have a film over them.

[Heavy Oil Saw]

Well it’s all together. Bought another rear handle, it’s in better condition, going to use the “original” on the second 261 I build from all the old parts I have left over and watch it burn as it fails.

Rebuilt the carb, left out the strainer, flushed out the 90 deg plastic coupler, and surprisingly wood dust came out of it. For some reason I was sent a Wartec air filter, are these any good?

Waiting on drum, clutch bearing, washer, e clip and tent vent, and then done and run.

For some reason I almost forgot the c clip on the crank end, behind the oil pump, what does it do? I’m thinking it helps clamp the oil pump drive arm to allow it to drive the pump.

On the subject of the oil pump, is that tiny rubber ring meant to seal the oil out put of the pump? Is the drive arm meant to clamp round the plastic drive spigot? I’ll drive the engine with a drill to test the pump, but I’d prefer to iron out any niggles while the saw is “dry”. Thank you for any help and putting up with my posts.

Here’s some pics (as always). That’s my dog leaving as she hates me working on the saw.

[MattyF]

You left out the gauze filter ?? Not a good idea.

[Heavy Oil Saw]

Gauze fitted.

[Heavy Oil Saw]

Stripped the centrifugal clutch assembly, it was full of what appears to be rust


Stripped it using long nose, my spring puller is at work. Looks a lot cleaner, and I’m happier when things are cleaner.

And all back together

What is the wear limit on the friction lining? I can’t see a wear indicator, or find anything obvious online.

[Stubby]

1 hour ago, Heavy Oil Saw said:

Stripped the centrifugal clutch assembly, it was full of what appears to be rust


Stripped it using long nose, my spring puller is at work. Looks a lot cleaner, and I’m happier when things are cleaner.

And all back together

What is the wear limit on the friction lining? I can’t see a wear indicator, or find anything obvious online.

I have found , in the past ( on a Husqvarna 357 that I used extensively ) that the drum wall thickness wares thin ( I am talking lots and lots of hours ) and the clutch explodes even when there is a lot of friction material left . I would check the drum as well . This saw I inherited from someone else and if it was mine from the get go this would not have happened as I don't use the chain brake ! ?

Edited April 7, 2020 by Stubby

[Heavy Oil Saw]

I have found , in the past ( on a Husqvarna 357 that I used extensively ) that the drum wall thickness wares thin ( I am talking lots and lots of hours ) and the clutch explodes even when there is a lot of friction material left . I would check the drum as well . This saw I inherited from someone else and if it was mine from the get go this would not have happened as I don't use the chain brake ! [emoji4]

I’m getting a new drum, .325 7T spur drum, then it’s bar and chain time. Been on chainsawbars, but not sure what length to settle on, I’m thinking 15” as a general purpose.