Cannot start MS260

[lone wolf]

Both- often I will pull a flywheel to get a good deep clean under and NOT remove the cylinder on old used saws that come to me that I intend on keeping for myself. I am talking that much gunk in and around the ignition starter side half that the coil is buried type filth.
Paid to repair saws are charged by the hour- eat your dinner off of clean is not required nor expected by the owner and most would be miffed to see a deep cleaning charge added to an invoice.
If it is agreed to prior- sure, if not they get what I deem to be safe, that might be solvent and compressed air- or high pressure waterblast to the areas to be worked on.
But like I said, each to their own and if you have the time and the tooling- pull whatever you deem necessary- its just in this particular case, at this stage of the game, an owner with this level of experience and lack of tooling- for an MS 260 and to inspect the internals of the engine enough to try and determine a cause- the flywheel can stay in place and negate any possible further mishaps as described elsewhere.

Prob a good idea to leave it on at this point until we know the cause. If the seals leak then that another story.

 

[ZeroJunk]

So you don't get dirt in the case when you pull the cylinder. Do you want to finish cleaning that filth up with the cylinder off? Also makes scraping the gasket surface clean a lot easier.

Since the saw had some sort of lean condition you want the clutch and flywheel off to give it a pressure test and be able to see the seals. If the seals fail you already have them exposed.

I ponyed up the $10 years ago and brought a real flywheel puller instead of using one of the various cave man methods, I don't regret it. Soft nylon rope works fine for a piston stop.

I do nice clean work on my saws........View attachment 1147084

View attachment 1147086

I know I am a heathen, but I plug the intake and exhaust, souse it down with Gunk Engine Cleaner and blast the hell out of it with a water hose.

 

[Sidecarflip]

One issue I don't have as I don't fiddle with other people's saws as a rule. The exception will be the Dolmar I have presently and it's a turd so I'll have to give it a bath prior to doing anything with it. I'll most likely give it a load of Zep degreaser and then pressure wash it with a low impact nozzle.

My saws never get cruddy, I'm anal about keeping them clean.

 

[lone wolf]

I know I am a heathen, but I plug the intake and exhaust, souse it down with Gunk Engine Cleaner and blast the hell out of it with a water hose.

If the bearings get wet, blow them out with air then WD them, then blow off again and oil with 2 cycle. And use hot water and a black rubber hose.

 

[Bob Hedgecutter]

If the bearings get wet, blow them out with air then WD them, then blow off again and oil with 2 cycle. And use hot water and a black rubber hose.

Is the black rubber hose to beat the saw into submission?
We are all getting sidetracked here- lets get a smeared out MS260 piston out of its nest.

 

[lone wolf]

Is the black rubber hose to beat the saw into submission?
We are all getting sidetracked here- lets get a smeared out MS260 piston out of is nest.

It is to beat the dirt!

 

[Sidecarflip]

If the bearings get wet, blow them out with air then WD them, then blow off again and oil with 2 cycle. And use hot water and a black rubber hose.

My pressure washer is a hot water diesel fired one.

 

[lone wolf]

My pressure washer is a hot water diesel fired one.

Just dry the clutch bearing after.

 

[ZeroJunk]

If the bearings get wet, blow them out with air then WD them, then blow off again and oil with 2 cycle. And use hot water and a black rubber hose.

Gets back to how old is the saw, or maybe more appropriately how much has it been used. If it is an older saw I replace the seals as matter of course. And, you can check the bearings then as well.
But, if it is a fairly new saw that has had a fuel mishap. I don't see the point.

Flipping them upside down and setting them out in the Sun works for me. Then a good dose of whatever, I buy WD40 by the gallon, will get it slicked back up.

 

[ZeroJunk]

It is to beat the dirt!

It's all good for the OP. He can get that saw up and running, and be proud of himself for doing it.

More than one way to skin a cat as well. He'll pick one.

 

[Mad Professor]

If the bearings get wet, blow them out with air then WD them, then blow off again and oil with 2 cycle. And use hot water and a black rubber hose.

I rinse it out with dry gas/isopropanol then mix.

 

[lone wolf]

I rinse it out with dry gas/isopropanol then mix.

And re oil?

 

[Mad Professor]

And re oil?

It gets oil in the mix.

First the alcohol X 2 rinses, rinses out ALL the water. The mix X 2 rinses, rinses out the alcohol and carries the oil to the bearings better than a thick oil itself, and also coats the crank and cases.

 

[Yukon Stihl]

I'm telling you, that piston is 100 percent shot, I have built hundreds of saws! Take my word for it, take it apart.

The only thing i would add to this is a pressure, vacuum test would help to find out why the piston looks like it does.
But if you are new to working on 2 cycles you need to do some reading and learning.

 

[holeycow]

It's probably about the simplest engine to work on in the history of engines. Except it's small. And it's german, not swedish...

Other than that, no biggy.

 

[ZeroJunk]

It gets oil in the mix.

First the alcohol X 2 rinses, rinses out ALL the water. The mix X 2 rinses, rinses out the alcohol and carries the oil to the bearings better than a thick oil itself, and also coats the crank and cases.

That crankcase probably won't hold a cup of mix. I have filled them up with mix and poured it back out a couple of times. A spray can of 2-26 with the case upside down will get that water out as well, what it's made for.
I take my finger and rub 2 cycle oil in the cylinder when I put it back together. I have used moly grease on my finger.
Never seen it make one bit of difference.

 

[cookies]

I'm gonna put possible blame on my honda trimmer for this mess. Its little 4-stroker has its own 1 gallon gas can with no mix. Maybe I used that once for the saw, who knows.

The thing is it seemed like a long process of deterioration, with the saw just getting more and more difficult to keep running. In the end it would stall out if I put it down, or if it was hot, or if I picked it up too fast. Something leaking and making it too lean maybe?

Oh you've gone and done it now saying you'll repair it yourself with a little help, Stirred everyone up really good getting them all excited to help you haha
Step 1 pressure/vac test....you must start here. If all is well you just work on the piston/cylinder...If it leaks down you will be tearing the saw fully apart.
Step 2 Clean Clean Clean before you open the saw engine, you should be thinking in your mind its so clean I'd eat off it. I use two methods...For only cylinder/piston removal I'll use solvent/compressed air to clean. If im going to tear it down to its crank then every part including the muffler gets a diesel bath with a parts brush scrub followed by a soap and water bath or two and more of the brush. You do not want any crap in your fresh engine!!
Once you get this far It's time to evaluate and make a parts list to order

 

[Mad Professor]

That crankcase probably won't hold a cup of mix. I have filled them up with mix and poured it back out a couple of times. A spray can of 2-26 with the case upside down will get that water out as well, what it's made for.
I take my finger and rub 2 cycle oil in the cylinder when I put it back together. I have used moly grease on my finger.
Never seen it make one bit of difference.

Is a spray going to get inside the lower end bearings completely? And rinse it out completely?

I used to teach organic chemistry, I know many ways to get rid of water. Rinsing with alcohol is one of the best, and inexpensive. I always have a stock of dry gas for my 4-stroke engines handy.

A can of isopropyl dry gas (better than methanol, it mixes better with pre-mix) will rinse the case completely several times. You can even turn the crank a few times with the case full. Do that before the mix, slosh it around then let it drain between each rinse

If you want to get a light coating of oil inside the case, and flush out more crud, yes a cup of mix. 3 whole cup fulls won't cost you a $1. You won't leave a pool of oil in the case either. It too will get into every crevice in the case.

If you are going to store it without putting it together, mix up some 10:1 for more residual oil.

 

[lone wolf]

Is a spray going to get inside the lower end bearings completely? And rinse it out completely?

I used to teach organic chemistry, I know many ways to get rid of water. Rinsing with alcohol is one of the best, and inexpensive. I always have a stock of dry gas for my 4-stroke engines handy.

A can of isopropyl dry gas (better than methanol, it mixes better with pre-mix) will rinse the case completely several times. You can even turn the crank a few times with the case full. Do that before the mix, slosh it around then let it drain between each rinse

If you want to get a light coating of oil inside the case, and flush out more crud, yes a cup of mix. 3 whole cup fulls won't cost you a $1. You won't leave a pool of oil in the case either. It too will get into every crevice in the case.

If you are going to store it without putting it together, mix up some 10:1 for more residual oil.

And as a bonus if you get it running shortly after all this it surely will clear it all out.

 

[lone wolf]

https://chemistry.stackexchange.com/questions/50741/how-does-wd40-displace-water