MS361 won't start?

[MagraAdam]

Hi guys, I've got a 361, and I love it. Light and powerful enough for what I do. It was in storage over winter and I had it running a couple of weeks ago for about half a tank. No issues. Today it won't start.

Has spark
Air filter is clean enough
Exhaust seems clear but I took it off and still no ignition
Has fuel
Has compression (and see photo for piston health)

I'm stumped.. any thoughts?

I mean, maybe I flooded it and didn't let it dry enough before trying again... But I've never flooded this saw before.



Thanks,

Adam

 

[buzz sawyer]

Can you explain the steps you take when starting?
Fresh fuel mix?
On mine, I set full choke, pull till it pops (4 - 5 pulls). Then half choke, pull till it runs (2 - 3 pulls) and let it run fast about 15 - 20 seconds, then let it idle down and run for a minute or so before cutting.

 

[MagraAdam]

Can you explain the steps you take when starting?
Fresh fuel mix?
On mine, I set full choke, pull till it pops (4 - 5 pulls). Then half choke, pull till it runs (2 - 3 pulls) and let it run fast about 15 - 20 seconds, then let it idle down and run for a minute or so before cutting.

I do the same, but maybe fast run for less time and let it warm up before I cut anything. But it wouldn't pop on full choke.

The fuel was working a couple of weeks ago..

 

[sand sock]

Hi guys, I've got a 361, and I love it. Light and powerful enough for what I do. It was in storage over winter and I had it running a couple of weeks ago for about half a tank. No issues. Today it won't start.

Has spark
Air filter is clean enough
Exhaust seems clear but I took it off and still no ignition
Has fuel
Has compression (and see photo for piston health)

I'm stumped.. any thoughts?

I mean, maybe I flooded it and didn't let it dry enough before trying again... But I've never flooded this saw before.

View attachment 935577

Thanks,

Adam

it is the fuel line. i change mine out every year, it fails as soon as it gets used after setting for a few summer months. i dont know if it is the summer heat, or you just hit that majic number of gallons of fuel used. its like clock work for mine though. it s a simple 30 minute job and $12 part.

 

[Stihl-Pioneer]

It looks quite wet in there from the pic to me. Possibly flooded it. Have you tried a new plug? I’ve seen a plug on a saw just not want to work sometimes.


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[axeman088]

The carbs on those saws are finicky. If the saw was stored dry with no fuel in it . The residues left behind after the gas evaporated have probably plugged up the carb so it won't draw enough fuel when new fuel was introduced into the carb after sitting . Most likely culprit is that inlet screen in the carb or the idle circuit in the carb. I have a few of these 361 and I am not a big fan of the saw because to me it is hard starting compared to other Stihl's I have.

Try this. Pull the plug out and make sure it is dry. Pull the engine over to clear the cylinder . Put the plug back in . One or two pulls on full choke . Move the lever up to the high idle position and then pull the engine over a few times quickly. It should at least try to fire and run . If it fires but doesn't want to stay running it is a carb problem.

 

[buzz sawyer]

it is the fuel line. i change mine out every year, it fails as soon as it gets used after setting for a few summer months. i dont know if it is the summer heat, or you just hit that majic number of gallons of fuel used. its like clock work for mine though. it s a simple 30 minute job and $12 part.

Surprising, I''ve had mine for at least 6 years and never had a fuel line problem. I'll have to check it out. I use only non-ethanol fuel.

 

[MagraAdam]

So, left the piston down and exhaust off for 24hrs, so it was nice and dry. Put it back together and gave it a few pulls on full choke. No pop. Plenty of fuel in the cylinder. Moved to half choke and no pop. I confirmed again that is had spark and no issues there.

 

[Vintage Engine Repairs]

So, left the piston down and exhaust off for 24hrs, so it was nice and dry. Put it back together and gave it a few pulls on full choke. No pop. Plenty of fuel in the cylinder. Moved to half choke and no pop. I confirmed again that is had spark and no issues there.

Hey mate

Hmm that’s a lot of blow by which could indicate the piston rings are worn out / low compression and thus starting issues or crappy old fuel mix.

However, empty the fuel tank, take the spark plug off and pull it over 10-15 times with WOT with no choke - this will clear the crankcase of any fuel.

Then, drop a teaspoon of 2 stroke mix (fresh, like today from the pump fresh!! NOT the stuff that’s been venting in the fuel tank for 4 weeks and a year in the Jerry can proior to that ) into the plug hole and put the plug and lead back in.

Turn the saw to the first position (which is on WITHOUT choke)

Hold the trigger down so you’re at wide open throttle and pull it hard 10 - 15 times and see if you get anything

If it is indeed low on compression, it will have a harder time running on old, stale fuel.

Give it every opportunity to work with fresh mix and take the carb, filter, lines etc out of the equation

 

[MagraAdam]

Thanks mate. I'll give that a go.

 

[Vintage Engine Repairs]

Thanks mate. I'll give that a go.

Can’t wait to hear, keep us updated! And if you do want to check the rings and fit some new ones I’d love to keep updated with that project too!

 

[buzz sawyer]

Just to cover all the bases, have you tried another plug? I remember I once had a plug with the ceramic broken around the center electrode. Looked fine when I held it up and checked for spark but when installed, the ceramic slid down over the electrode and blocked the gap.

 

[Vintage Engine Repairs]

Just to cover all the bases, have you tried another plug? I remember I once had a plug with the ceramic broken around the center electrode. Looked fine when I held it up and checked for spark but when installed, the ceramic slid down over the electrode and blocked the gap.

Haha how annoying must that have been!

 

[Binthewoods]

I'd disconnect the fuel line from the carb and see if you can get it started with fuel squirted into the cylinder.

If it won't start that way then I'd check the flywheel and make sure the key didn't shear.
If it does start then I'd start looking at the carb and choke, is the choke opening/shutting correctly? Is the carb needle stuck?

Good luck!

 

[CentaurG2]

Give it a good swift kick. Always worked with mine. Seriously, that saw is VERY easy to flood as it actually has a half choke position on the carb so if you miss the burb, you are done. Put everything back together, tape or zip tie the throttle to full, put the stupid switch to run, and pull her guts out. It might take 40 or so pulls but it will eventually clear and sputter to life. Be careful, you now have a saw with the throttle pined wide open. You can remove the throttle pin or just shut it off and remove the pin. It should act normally unless you flood it again.

 

[PaladinMan187]

So I had this issue with mine. Come to find out it was a coil that wasn't putting out enough to fire it off. It might have fire but not quite enough to get the job done. Not a sermon. Just a thought.

 

[Canyon Angler]

As Centaur said, try putting it on "run" (no choke), then hold the throttle WFO and pull pull pull pull pull pull pull pull pull pull pull pull pull until you're winded, then do it again until you're winded 3 or 4 more times. It should start. DAMHIKT (Oh, and don't use the compression release -- that's a great way to get it to not start IME.)

I've had my 361 for 12-13 years and I've never had to replace the fuel line, though I never use gasohol... (Watch: Tomorrow the fuel line will go!)

 

[Vintage Engine Repairs]

Any updates Adam?

 

[MagraAdam]

Any updates Adam?

Yep, I followed your advice today after work. So it had 24hrs with the plug out and no fuel in the tank or lines. After chucking a teaspoon of fuel in and putting the plug back in it started up. Oh. I had the filter off too in case that was the problem. It started first pull. I topped it back up with fuel and it ran and cut. So I'm stumped as to what it was other than flooding or the fuel went bad (which would be odd given I used the same Jerry of fuel today and what it had in it was half a tank left over from cutting a couple of weeks ago..)

Thanks all for your help!

(Let's hope it runs next time I want to cut..)

 

[Vintage Engine Repairs]

Was the fuel that you used when it wouldn’t start, left in the saws fuel tank for a couple of weeks? Or did you have that tank empty on your saw for 2 weeks and add new fuel from the Jerry can?