Stihl MS361 help for a newbie

[bmp01]

Well this is a fun thread.

There's only one rule - you have to let us know when you get it running and report on your findings.

[bmp01]

Going back to why saw won't fire even when you've added fuel; 

Have you swapped in a good spark plug ?

Have you tried getting the ignition system to jump a big plug gap ? It's sometimes the case the ignition appears to work with the standard plug out of the engine but once plug is under pressure in the cylinder it falls over.

WRT timing - what matters is piston position when flywheel is passing the coil. There will be variations in coil design and in the advance curves within the electronics of the coil but you'll get some idea if things are about right if you compare this one with your 260.

 

Good luck.

[chopchop]

Hey all and thanks again to those who have contributed. Very useful.

 

So the seller has paid the money back to my account so I effectively have a free saw! Shame it's no a Stihl but there goes.

 

The compression check I did with what I believe is a standard car jobbing so probably not accurate. Have not seen any with Schrader valves online. 

 

The compression is a hard one to judge. With the decomp out it does not fall on the cord at all. It is also very very hard to pull over at all. With the decomp in it falls on the cord easily...too easily with little resistance. 

 

Reckon the first job is to plug that decomp hole as suggested (thank you). Then a brand new plug and fresh fuel mix. 

 

I have mostly stripped it again and nothing looks odd to me. However I haven't investigated the bottom end as yet. Interestingly, considering the condition of piston, rings (good and springy) and cylinder, the piston rod stands out. Almost a dark rust colour. Also the bearings are different. There's the suspect red one under the flywheel and a cream coloured one beneath the clutch. 

 

One last thing of note is that when I tried to take one of the bar studs out using the double nut hack, it came out surprisingly easily. Haven't tried the second just yet. Do they both hold the crankcase together on a 361? 

 

Finishing putting down a floor and then I'll have another look. 

 

Atb all.

[ChrisNewport]

no need to remove the bar studs they dont hold the cases together, there are 5 screws that do this, 3 in the clutch area and two just behind the dawg spikes.

[Muddy42]

Its best to approach this systematically. Please think hard about splitting the crankcase and eliminate all other problems first.  It can be very hard to seal the bottom end properly and shouldn't really be necessary unless you have an air leak in the seals or some other issue down there.  Pressure and vac test first.

[john87]

Take the plug out, Heat the end up until is is nearly red. Refit it as fast as you can and try to start it. This usually never fails. Give it a try..

 

john..

[pleasant]

4 hours ago, chopchop said:

Hey all and thanks again to those who have contributed. Very useful.

 

So the seller has paid the money back to my account so I effectively have a free saw! Shame it's no a Stihl but there goes.

 

The compression check I did with what I believe is a standard car jobbing so probably not accurate. Have not seen any with Schrader valves online. 

 

The compression is a hard one to judge. With the decomp out it does not fall on the cord at all. It is also very very hard to pull over at all. With the decomp in it falls on the cord easily...too easily with little resistance. 

 

Reckon the first job is to plug that decomp hole as suggested (thank you). Then a brand new plug and fresh fuel mix. 

 

I have mostly stripped it again and nothing looks odd to me. However I haven't investigated the bottom end as yet. Interestingly, considering the condition of piston, rings (good and springy) and cylinder, the piston rod stands out. Almost a dark rust colour. Also the bearings are different. There's the suspect red one under the flywheel and a cream coloured one beneath the clutch. 

 

One last thing of note is that when I tried to take one of the bar studs out using the double nut hack, it came out surprisingly easily. Haven't tried the second just yet. Do they both hold the crankcase together on a 361? 

 

Finishing putting down a floor and then I'll have another look. 

 

Atb all.

The issue here (well, for me at least) is you are tryrng to make a poorly engineered and assembled machine better that when it was designed in china and when it was assembled using crap parts. Lke I said in an earlier post, it has probably never run given the condition of it. Hell, a mcculloch is better engineered and put together than one of these. In essence, trying to improve on a poor quality saw using the same components it came with is not going to happen. You have a 40 quid saw for which you paid 40 quid for and you have your money back. Whatever happens at the end of this you wont have an ms361.....you will have a poor unreliable, dangerous saw worth 40 quid. Just because it has ms361 on it and it looks similar, it does not make it a 361.

 

Sorry, but thats just my opinion.

 

We see this kind of thing all the time with online purchases of generic garden machinery...first thing that fails is the recoil. We cant repair them because we know it will fail soon after and we will be repairing it again and again for nothing. I tells customers we cannot improve on how its been designed....which is cheap.

Edited April 12, 2023 by pleasant

[spudulike]

Please forget splitting the crankcases and start using the grey matter. The bar studs have nothing to do with holding the cases together and in doing this, you are just showing your inexperience.

The saw isn't running - only a saw with a massive air leak will not run, small air leaks cause other running issues but the saw will fire and run.

You seem to have verified that the saw has compression. It is relatively unlikely your HT system is that bad but if you take an old plug and bend the end electrode well away from the centre electrode, you can test the spark over a big gap. If it sparks, you are most likely OK.

I said most saws issues are carb issues and that is....because they are. I think you said that the carb had petrol in both sides. It is quite possible that the needle valve isn't sealing off correctly which would stop the saw running, if you have a Mityvac or pop off tester, you can test the valve. If you don't have this equipment, stick a bit of pipe on the fuel union, suck on the pipe and stick your tongue over the end. Your tongue should stick to the end of the pipe and stay there. If it doesn't do this, the issue is with the needle valve.

Your compression gauge sounds like a car one which isn't suitable for small engines - many use schrader valves but the ones for small engines have a valve that opens up with very little pressure and that is the difference.

 

[chopchop]

11 minutes ago, pleasant said:

The issue here, is you are tryrng to make a poorly engineered and assembled machine better that when it was designed in china and when it was assembled using crap parts. Lke I said in an earlier post, it has probably never run given the condition of it. Hell, a mcculloch is better engineered and put together than one of these. In essence, trying to improve on a poor quality saw using the same components it came with is not going to happen. You have a 40 quid saw for which you paid 40 quid for and you have your money back. Whatever happens at the end of this you wont have an ms361.....you will have a poor unreliable, dangerous saw worth 40 quid. Just because it has ms361 on it and it looks similar, it does not make it a 361.

 

Sorry, but thats just my opinion.

 

We see this kind of thing all the time with online purchases of generic garden machinery...first thing that fails is the recoil. We cant repair them because we know it will fail soon after and we will be repairing it again and again for nothing. I tells customers we cannot improve on how its been designed....which is cheap.

No that's fair enough and I know that deep down. Might just park it in the garage. The work, hassle and investment I'd be happy with if it was genuine. But I'm looking at trying to fix a saw I have little confidence in working no matter what I do. Different with a stihl as you know they will work if you work through the diagnostic process. 

[pleasant]

21 minutes ago, chopchop said:

No that's fair enough and I know that deep down. Might just park it in the garage. The work, hassle and investment I'd be happy with if it was genuine. But I'm looking at trying to fix a saw I have little confidence in working no matter what I do. Different with a stihl as you know they will work if you work through the diagnostic process. 

Yes, thats correct. You are spending a lot of time and money on a saw, which at the end of it, is still only worth 40 quid (bet youve spend more than that already) everyone here has been very helpful and are knowledgeable, however suggesting ways to fix one of these in the same way as you would suggest fixing issues with a genuine stihl saw are streets apart and the same criteria is not a case of 'one size fits all'  admittedly basic checks are the same or similar, but after that who knows given the quality of this stuff...these were made to con people on ebay, boot fairs and pub car parks and would start and run long enough for someone to part with a few hundred quid. like you say, you may get it running, but its still not a 361.....probably less so a ryobi, and you wont have any confidence in it just waiting for the next thing to break or for it to let you down.

Even a broken chinese rolex is right twice a day!

 

Edited April 12, 2023 by pleasant