MS361 help, saw will not stay running!

[onebadsob3]

Been searching the webs for help with my saw but the more I look, the more I am at a lost.

Some years ago, I went to use it after letting it sit for a while and if I remember right, it turned off when putting it on its side to cut into a tree. I cleaned the carb and put it back together and it seemed fine for a while, thought maybe it had trash in it. Well, I guess last year I tried to use it and it would not stay running. I maybe rebuilt the carb again but that didn't fix the issue so I bought an aftermarket Dukes carb I think. The saw would run with it on it but it just didn't seem like it would rev up like it should so I was never satisfied with it.

This year I knew we need to cut some wood to have some for our stove so I made it a point to fix this saw. I took the original carb and put it in cleaner, took everything I knew to take apart and cleaned it, sprayed carb cleaner in holes and even tried to push wire through holes. Needless to say, I put it all back together and crank it up and it seemed to run great. Sharpened the chain and I was ready to cut.

Saturday, I put the saw in wood and it ran good but didn't even make it through a log. At WOT, it just died. I could choke it and it would fire back up but once you go WOT again, it dies again!

After reading some things, some say the fuel line but I am pretty sure I replaced and the tank filter at some point, last year I guess. Reading some more, it seems like some said maybe the needle wasn't opening up enough at WOT and it was running out of gas so I took it out tonight and barely bent it to pull up the needle more so that it would get full flow. Put it back together and cranked it up. Seemed to be running good but I decided to hold it WOT a little longer and then it just died. Same situation that I have been fighting forever it seems like. It'll crank back up, run and then die again.

The saw is not beat up, wore out or abused by any means.

I'm just at a lost and really don't know what to do or check for. If I remember correctly, the Dukes carb did run on the saw, so to me that means that the fuel line is good, no ignition issues or fueling issues. I just didn't think it was as strong as it used to be so I wanted to figure out why the original carb will not work. Last I checked, I think one place had a Stihl carb and it was around $100 which is a fifth of what I paid for the saw. If it is in the carb though, I just don't know whatelse to change, clean, check or replace to make it run like it should.

It was cleaned and blown out, maybe didn't get it all of the way but I'm not certified chainsaw mechanic, more or less and a guy that does what he thinks is right or will go by a video.
L and H screws I think are set 1-1/4
Pretty sure I replaced the fuel line and filter in the last year or two but it had problems after changing those.
Put the plug to Winter mode tonight to see if that made a difference but it did not.
I rebuilt the carb with the gaskets a couple of times since it acted up some years ago but nothing has worked in fixing it.
For last 5 or so years, we only use ethanol free gas with the gray stihl bottle mix, performance xp or something like that.

Sorry for the long post and rambling if I have but I am so confused with this saw. Any help or ideas is appreciated, thanks,
Charlie

 

[Mad Professor]

Pull you muffler and check the piston. Take a picture.

If that's OK I'd pressure/vacuum test the saw itself and the carb and fuel tank (vent)

welcome

 

[pioneerguy600]

Yes, first step is to pull the muffler off and check the piston condition looking through the ex port. It costs nothing money wise just a few mins will tell a whole lot when a saw is acting up like this one is. I f you do enough of this diagnostic stuff for long enough you can actually feel the engine condition by just slowly pulling out the recoil and feeling the engine turn over several times but until you develop those skills its best to pull the muffler and look.

 

[Aknutter]

Check the muffler screen, make sure it's not plugged with carbon while apart.

 

[Drillerman]

Check the muffler screen, make sure it's not plugged with carbon while apart.

Had a leaf blower do this to me, burned off the carbon on the screen with a torch and it worked great, sadly I didn't check the screen before messing with the carb settings. Good luck!

 

[HansFranz]

Check the muffler screen, make sure it's not plugged with carbon while apart.

That's always the first thing I check. My 361 plugged up that way a few times before I muff modded it.

If the screen is plugged with carbon, you can pull out the screen (you need to remove one screw to slide it out), then heat the screen over a propane torch or gas stove flame to burn off the carbon, then replace it and try again.

Might also want to check/replace the fuel filter in the tank,

 

[stihltech]

Doing a lot of "I tried this, then this, then this".
Now let's diagnose.
Does it hold the saw up when held by the starter handle?
What does the fuel look like in a glass jar?
Pull the muffler, what does the piston look like?
Any dampness around the cylinder gasket?
Are the cylinder screws tight?
This is just a start.
Too many saws do not get a problem solved because a plan is not followed.
This is why Stihl wants you to learn a diagnostic sheet. It is a plan.
Works well.

 

[guym3]

Feel your pain!
Couple of points. Fresh fuel is vital. I had a brush cutter doing this and fresh fuel sorted it straight away.
Also you say how far out the H and L screw are, but not that you've tuned the carb properly. If you've been sticking bits of wire through holes in the carb it may need a very different H and L setting to factory.
Good luck.

 

[onebadsob3]

I'm sorry for the late response but I was busy over the week and I have tinkered with it but I just haven't had the chance to get on the computer during the week. I'm going to go thru this post and really try to pin point the issues I'm having if my issue is not fixed!

As mentioned, the saw is not abused or wore out, I really have not used it a whole lot since I got it and that was when it was like new if not new!

It definitely is not low on compression. No, it is not tuned to right specifics, but when it was acting up, nothing had been tampered with and you only had slight adjustments on the h and l idle screws. I'll pull the muffler and check the piston and even take pictures and report back.

During the week, I reinstalled the dukes carb on it and the saw seems to run good, maybe not having the screws adjusted properly but it maybe seemed like might be running a little rich. It never cut off at high throttle during my testing. I ended up taking the original carb, using some small wire to just make sure there was no debris or clogs in any holes it had and spraying them out with carb cleaner.

The saw has not been used that much that it still had the original spark plug and air filter on it. I replaced the plug and got a new filter for it. Tried to put the arm that holds the fuel needle seat back to where it was, put it back together and put it on the saw.

Have not physically put the saw in wood, but the saw seems like it is staying running at idle and it has not cut off while running it at a high throttle for an extended time.

The weather has been nasty in NC so when I get a chance, I'm going to try it, go thru the post and do the things you guys have recommended and report back.

Thanks for the help so far!

 

[onebadsob3]

Here is an update, still not good. The saw seemed like it was fixed just messing with it around the house but I took it to the farm yesterday and put it in a log. Did the same exact thing. Was running good, throwing out good chips and then it died at WOT. Was able to choke it and crank it back up and then rev it and it would die again. Finally got it running and and ran it half throttle to finish the cut and then later I believe it quit again.

Still not sure if the carb is the issue or not? Guess I need to put the Dukes aftermarket back on and run it and see if it will run or not.

Here is what I know.
Fuel tank is clean and had fresh gas in it. Been running the same gas mix in the other saws and not having any issues. Use non ethanol gas and stihl mix.
I took the muffler off and the piston has rings on it and I don't see anything wrong inside the cylinder.
The spark arrestor screen is clean, nothing blocking it.
Holding saw by the cord, it maybe moved 2 clicks but not far as it then held it up in the air without dropping anymore, could have been where it was at on the stroke.
I did a compression test on it tonight, muffler off and carb not tightened down, just on the studs, but it was reading between 150-155 each time and I did it 3 times.
Checked the head screws and they were all tight.
Have not done a pressure test but I guess I need to look into that. I think we have a pump but it is old so I'll have to dig it out.

One said "If that's OK I'd pressure/vacuum test the saw itself and the carb and fuel tank (vent)". Sorry for not knowing but what exactly do you mean by that.

I also know for a fact that I bought 2 new fuel lines a year ago, so I am thinking that I replaced the one on the saw, but at the moment, I can not find the spare but it could be at the farm.

Posted pictures of the saw from today, sorry if it doesn't show up good but sometimes a Samsung camera just doesn't do close ups as good as an apple.

Once you get this saw in a log though and start cutting, it is almost like clockwork when it dies each time.

 

[HansFranz]

...put it in a log. Did the same exact thing. Was running good, throwing out good chips and then it died at WOT. Was able to choke it and crank it back up and then rev it and it would die again. Finally got it running and and ran it half throttle to finish the cut and then later I believe it quit again...Once you get this saw in a log though and start cutting, it is almost like clockwork when it dies each time.

I'm far from an expert or even competent at fixing saws, but is there any chance it's the coil breaking down when it gets hot? (My question is mainly for the more knowledgeable folks here, maybe they'll chime in again if that potential problem fits the behavior of the saw.) If not that, then I would assume it's not getting enough fuel for whatever reason...

 

[ZeroJunk]

Stihl makes an in line spark tester that works well and you can cut with it in place. If it starts skipping or losing spark it jumps out at you.
There are other testers but they seem to be heavy and clunky and hard to turn at a sharp angle.

 

[pioneerguy600]

The way this saw is acting is a bit different than the ones I have had experienced spark module failing but it very well could be the electronic chip that controls the spark timing is failing, most fail when heated up and will not restart until they cool off some but my friend and neighbor had one go out on his Jonsered , it was acting much like the OP`s and we fixed it with a cheaper AM module. Not my choice but he is a cheap SOB and actually proud of being so.

 

[stihltech]

Have you tried opening the fuel cap when it starts to die and see if the performance comes back? I am still betting on a tank vent before an ignition, from experience on repairing these units.
Pull a vacuum on the empty fuel tank. It should not hold and drop fairly quickly.

 

[SteveSr]

Looks like a JUNK AM cylinder. Take a look at the port edges in the photos...

 

[onebadsob3]

Hopefully this is the last update to this story. I never knew about the tank vent because I did not know the location of it. Really don't tear into the saws that much but I could if I needed to but I just always thought it was something up with the carb. Watched a video after my last post and tank vents and the guy showed where it was and how to replace it. His other video talked about his saw not running correctly and cutting off. He then described that the saw would crank back up by choking it but that was the only way. My saw was acting the same way. I didn't try what a previous poster said and what he said in the video by opening the gas cap and seeing if it would crank without choking it.

After thinking about it, I hadn't tried the impulse hose or the tank vent. Looked on Amazon and they had a 5 pack for like $11 and I could have them today, so I ordered some. Maybe not as good as stihl and maybe they are? It says they fit a MS460 and I have one of those and it also says that BR600 blowers have them and I have some of those so I figured I'll have spares if I need them.

Popped in the new vent today and started putting the saw back together. Printed out some diagrams of how the carburetor gaskets are supposed to be so I doubled checked them just to make sure they were correct and they were. Finished putting the saw together and it was time to try it out.

Cranked it up and went down to to a gully and found a log to put the saw into. Started cutting and it made it through, never cutting off or acting as if it was going to. Tried some more cuts and I ended up cutting through the log 4 times and the saw ran great with no issues. I'm assuming my problem has been fixed since it always in the past has been cutting off in WOT half way through the first cut into the log!

Not sure what you meant by the piston being a junk am cylinder but the saw is was like new when we got it and we haven't touched a thing on it other than the fuel line and carbuertors/rebuild kits trying to get it to run correctly all of these years when it was a tank vent.

I appreciate all of the help and hopefully the problem is resolved now

 

[djg james]

Hopefully this is the last update to this story. I never knew about the tank vent because I did not know the location of it. Really don't tear into the saws that much but I could if I needed to but I just always thought it was something up with the carb. Watched a video after my last post and tank vents and the guy showed where it was and how to replace it. His other video talked about his saw not running correctly and cutting off. He then described that the saw would crank back up by choking it but that was the only way. My saw was acting the same way. I didn't try what a previous poster said and what he said in the video by opening the gas cap and seeing if it would crank without choking it.

After thinking about it, I hadn't tried the impulse hose or the tank vent. Looked on Amazon and they had a 5 pack for like $11 and I could have them today, so I ordered some. Maybe not as good as stihl and maybe they are? It says they fit a MS460 and I have one of those and it also says that BR600 blowers have them and I have some of those so I figured I'll have spares if I need them.

Popped in the new vent today and started putting the saw back together. Printed out some diagrams of how the carburetor gaskets are supposed to be so I doubled checked them just to make sure they were correct and they were. Finished putting the saw together and it was time to try it out.

Cranked it up and went down to to a gully and found a log to put the saw into. Started cutting and it made it through, never cutting off or acting as if it was going to. Tried some more cuts and I ended up cutting through the log 4 times and the saw ran great with no issues. I'm assuming my problem has been fixed since it always in the past has been cutting off in WOT half way through the first cut into the log!

Not sure what you meant by the piston being a junk am cylinder but the saw is was like new when we got it and we haven't touched a thing on it other than the fuel line and carbuertors/rebuild kits trying to get it to run correctly all of these years when it was a tank vent.

I appreciate all of the help and hopefully the problem is resolved now

Congratulations! I'm in the same pickle with my 038 that you were with your saw. Same problem. And like you, not a lot of experience with repairing saws. I put a new vent in today and that didn't help. Tomorrow I'll check a few more easy things before attacking the carb.. Where did you buy your carb kit? AM? Any will do?

 

[stihltech]

Hopefully this is the last update to this story. I never knew about the tank vent because I did not know the location of it. Really don't tear into the saws that much but I could if I needed to but I just always thought it was something up with the carb. Watched a video after my last post and tank vents and the guy showed where it was and how to replace it. His other video talked about his saw not running correctly and cutting off. He then described that the saw would crank back up by choking it but that was the only way. My saw was acting the same way. I didn't try what a previous poster said and what he said in the video by opening the gas cap and seeing if it would crank without choking it.

After thinking about it, I hadn't tried the impulse hose or the tank vent. Looked on Amazon and they had a 5 pack for like $11 and I could have them today, so I ordered some. Maybe not as good as stihl and maybe they are? It says they fit a MS460 and I have one of those and it also says that BR600 blowers have them and I have some of those so I figured I'll have spares if I need them.

Popped in the new vent today and started putting the saw back together. Printed out some diagrams of how the carburetor gaskets are supposed to be so I doubled checked them just to make sure they were correct and they were. Finished putting the saw together and it was time to try it out.

Cranked it up and went down to to a gully and found a log to put the saw into. Started cutting and it made it through, never cutting off or acting as if it was going to. Tried some more cuts and I ended up cutting through the log 4 times and the saw ran great with no issues. I'm assuming my problem has been fixed since it always in the past has been cutting off in WOT half way through the first cut into the log!

Not sure what you meant by the piston being a junk am cylinder but the saw is was like new when we got it and we haven't touched a thing on it other than the fuel line and carbuertors/rebuild kits trying to get it to run correctly all of these years when it was a tank vent.

I appreciate all of the help and hopefully the problem is resolved now

Now you have learned something important that many miss. No air in, no fuel out.

 

[SteveSr]

Not sure what you meant by the piston being a junk am cylinder but the saw is was like new when we got it and we haven't touched a thing on it other than the fuel line and carbuertors/rebuild kits trying to get it to run correctly all of these years when it was a tank vent.

Well, it appears that the original owner burned up the saw and then rebuilt it with a cheap Chinese aftermarket piston and cylinder and at the same time failed to figure out and fix the tank vent that caused the problem in the first place.

AM P&C kits never run as good as OEM and will sometimes grenade when the piston pin clips come loose while running. If I were you and planned on using this saw a bunch I would start looking for a good used OEM piston and cylinder on Ebay or elsewhere.

 

[HansFranz]

Will a clogged fuel tank vent make a saw lean out and burn up? I never thought about it...I figured it would just act like it ran out of fuel.