Cannot start MS260

[Mad Professor]

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

Another option would be acetone, might be harder on the seals? But a quick rinse would be fine.

Methanol will phase separate with hydrocarbon solvents (mix), so it will get the water but harder to rinse out using mix later

If you want better solubility data, find an old version of: Lange's Handbook of Chemistry

It gives the actual solubility proportions volume:volume.

 

[mrman21]

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?

I know a lot of the posters to the forum will disagree but google and youtube are your friends right now . I don,t blame you for trying to learn , we all had to start somewhere . Use good quality parts and I bet there is a youtube video specific or very close to your model saw and step by step instructions . Good luck .

 

[ZeroJunk]

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.

I wasn't planning on getting water in there to start with. That was your plan.

And, thinking some minute amount of water left on the bearings after a water displacement spray at start up is going to do anything is a little anal don't you think.

 

[cookies]

I simply use some fresh mixed fuel to rinse the bottom end out a few times, pour a ounce or so in then rotate the crank using the rod half a dozen times then rapidly dump and repeat until its perfectly smooth turning. This has led me to catch more than one bad bottom end , use wide masking tape to cover the case opening to seal it if waiting for parts. The non e mix will remove moisture by agitation and dumping alone.

here is a rough list of needed tools for the op to aquire
pressure/vac tester I like the mightyvac version, search threads on here for adapters, gaskets etc to use with it and how too's...you will need to make some of the rubber seals, its simple
T handle T27, 19mm and impact gun (clutch removal), razor blades, dental or mechanics picks, #1 & 2 phillips and flat head screwdrivers, pocket flat head, hemostats 4 inch and 6 inch.
I prefer doing teardowns on unassembled shipping boxes, they absorb oil/fuel well while parts/tools stay on the box to reduce misplacing things. When disassembled and parts are cleaned up and ready to go I assemble the box and store everything in it if waiting for parts to come.

 

[Mad Professor]

I wasn't planning on getting water in there to start with. That was your plan.

And, thinking some minute amount of water left on the bearings after a water displacement spray at start up is going to do anything is a little anal don't you think.

You are the one who is going to "blast it with a hose".

 

[ZeroJunk]

You are the one who is going to "blast it with a hose".

I do. I also plug the intake and exhaust. If you get water in there then you sure enough have problems.

 

[Mad Professor]

I do. I also plug the intake and exhaust. If you get water in there then you sure enough have problems.

So do you block off int/ex like for a pressure /vac test?

That's the only way to ensure you won't get water/crud/solvents in there

absolutely, what I do every time

also I never use a piston stop, just leave the sparkplug in and zip the flywheel nut off with an impact driver, clutch could be done the same way also, with low compression I would certainly hold the flywheel with a rag during this process, coil off already

clutch off, then flywheel, need the flywheel on to get the clutch off without a piston stop


edit, realistically, you can just hold the saw by the top handle and whack the nut to knock the flywheel loose, or leave the saw loosely sitting on the bench, as long as the saw can move the weight of the flywheel will do the work for you

Puch Flywheel tool fits two sizes of flywheel thread, $19 delivered



Stihl tool (mine)

 

[ZeroJunk]

So do you block off int/ex like for a pressure /vac test?

That's the only way to ensure you won't get water/crud/solvents in there


Puch Flywheel tool fits two sizes of flywheel thread, $19 delivered

View attachment 1147618

Stihl tool (mine)

View attachment 1147619

Yes. If I clean the cylinder I run it through the dishwasher. If I have to split the case I run the case halves through the dishwasher. And, I use OEM flywheel pullers. There are several. OEM seal pullers..
It is what I do. But, if a fairly new saw is run with bad gas I am not going to pull the clutch or flywheel.
I will clean the case, get the transfer out, run the cylinder through the dishwasher, put a coat of oil on the cylinder...

 

[BillCinMA]

Hi!

Can anyone help me on what to try next here? My Stihl MS260 was not used for around a year or two. Now I cannot start it. I'm literally almost fainting with exhaustion pulling the cord after trying different things. Here's what I've tried so far. I never ever get any hint of combustion, it is as if it's completely dead:

1. Removed carb, dismantled, left if carb cleaner for a day, blown out all the holes.
2. Cleaned air filter - opened it in half and blew out from the inside.
3. Put in TruFuel 1:50 fuel from brand new bottle.
4. Tried spraying carb cleaner through the carb and starting.
5. Tried TruFuel through the spark plug hold - a dropper full, and then 3 droppers.
6. New spark plug. When I pull the plug and ground it, and pull the cord, I do see a spark BUT ONLY when I pull fast. When I pull at what I consider low to moderate levels I don't see anything.
7. Checked the spark arrestor - the fine mesh is completely clean.
8. Checked that fuel is being pulled up - I can see it at the top of the tube when I pull off the black rubber tube that goes into the carb. Fuel filter looks completely clean.

I've tried holding the carb on full speed mode (put a bungee on the handle to hold it open) and pulling dozens of times with it in run position. Nothing. Even when I have put fuel directly into the cylinder.

My guess is that the ignition system is weak and there's no spark inside the cylinder, despite me seeing sparks with the plug pulled and I pull the starter fast.

I'd truly like to fix this myself and understand what the problem(s) are, as I have another two saws that need similar TLC.

I had the same problem. Week spark. New cheep coil from eBay solved it.

 

[2StrokeFondler]

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

Upvote for stackexchange!

 

[deanbrown]

Update - I took off the exhaust to get to creating a rubber seal to pressure test (btw still waiting for tools to arrive). But one of the cylinder bolts was laying down completely out of its hole. Seems it had vibrated itself out of its thread. Sigh! I've never been in there before so that happened out of the factory. Should I be using threadlock on these bolts when the time comes?

 

[lone wolf]

Update - I took off the exhaust to get to creating a rubber seal to pressure test (btw still waiting for tools to arrive). But one of the cylinder bolts was laying down completely out of its hole. Seems it had vibrated itself out of its thread. Sigh!

Well, there is the vac leak. That will do it. Pull the cyl off and get some CLEAR pics of it and both sides of the piston. With some skill and luck, maybe you could clean the cylinder up and use a new OEM piston. It won't hurt to thread lock them after that .

 

[deanbrown]

Well, there is the vac leak. That will do it. Pull the cyl off and get some CLEAR pics of it and both sides of the piston. With some skill and luck, maybe you could clean the cylinder up and use a new OEM piston. It won't hurt to thread lock them after that .

I was waiting to pressure test it before proceeding any further. Wondering if there's any value in that now?

 

[lone wolf]

I was waiting to pressure test it before proceeding any furti her. Wondering if there's any value in that now?

Not really what matters is that it holds before you run it ! You can always put the cyl back on without a piston as a test, just to see later if you are impatient. But take it apart now and get pics, I have a feeling this was the problem.

 

[Bob Hedgecutter]

Update - I took off the exhaust to get to creating a rubber seal to pressure test (btw still waiting for tools to arrive). But one of the cylinder bolts was laying down completely out of its hole. Seems it had vibrated itself out of its thread. Sigh! I've never been in there before so that happened out of the factory. Should I be using threadlock on these bolts when the time comes?

No need to wait for tools- just a long shank T27 and take the other 3 cylinder bolts out- never seen a cylinder bolt rattle out and stay put- never seen one rattle out to be honest.
But the piston looks toasted from what we can see in the photograph- cylinder NEEDS to come off.

 

[lone wolf]

No need to wait for tools- just a long shank T27 and take the other 3 cylinder bolts out- never seen a cylinder bolt rattle out and stay put- never seen one rattle out to be honest.
But the piston looks toasted from what we can see in the photograph- cylinder NEEDS to come off.

I have seen them loose but not out.

 

[Bob Hedgecutter]

I have seen them loose but nor out.

Yep thats what I meant- loose and gasket blow out because of- but never right out- in my limited experience.

 

[deanbrown]

It fell down when I removed the exhaust can. I thought I was having trouble with my adding for a moment - two holes, 3 bolts?

 

[Bob Hedgecutter]

Show us a photo of the 3rd bolt- in the photo it almost looks too long and plain shanked to be a cylinder bolt.

 

[lone wolf]

It fell down when I removed the exhaust can. I thought I was having trouble with my adding for a moment - two holes, 3 bolts?

I'm starting to wonder if the hole is now stripped from it, dancing around before it came out? Could happen with lot of use.