Standard Troubleshooting Sequence?

[Canyon Angler]

Hey, all,

I have a MS361 I was using today that, after shutting it down, wouldn't restart an hour later. When I was using it earlier in the day, it seemed fine -- plenty of power, it was 4-stroking/burbling nice out of the cut, and cleaning up when under load, it had fresh fuel, etc. But I couldn't restart it even with lots of choking, even after pouring some mix down the throat and changing fuel filter and cleaning the air filter -- not even a pop. (It has a modded muffler so I didn't check the screen for getting carboned up yet.)

So my question is, is there a standard sequence that you more experienced guys look at when diagnosing a saw that won't start?

For example, I assume if I pull the plug and confirm that I have a nice strong blue spark, then I know I need to confirm that I'm getting fuel. But if I try a new spark plug and find that I have no spark, what then? (I've never replaced any ignition components on any of my saws, yet.) I haven't checked condition of piston/cylinder yet, mainly because I'm 99% sure it never went lean.

(What bugs me is that once or twice I've had this happen before with this same saw, and tried for HOURS to start it without so much as a pop, and finally took it to the dealer under warranty, and left it there -- and the dealer called back and said he started it up on the first or second pull. So after that, I take the time to make sure it's not flooded...)

Thanks for any clues.

 

[grizz55chev]

Hey, all,

I have a MS361 I was using today that, after shutting it down, wouldn't restart an hour later. When I was using it, it seemed fine -- plenty of power, it was 4-stroking/burbling nice out of the cut, and cleaning up when under load, it had fresh fuel, etc. But I couldn't restart it even with lots of choking, even after pouring some mix down the throat and changing fuel filter and cleaning the air filter -- not even a pop. (It has a modded muffler so I didn't check the screen for getting carboned up yet.)

So my question is, is there a standard sequence that you more experienced guys look at when diagnosing a saw that won't start?

For example, I assume if I pull the plug and confirm that I have a nice strong blue spark, then I know I need to confirm that I'm getting fuel. But if I try a new spark plug and find that I have no spark, what then? (I've never replaced any ignition components on any of my saws, yet.) I haven't checked condition of piston/cylinder yet, mainly because I'm 99% sure it never went lean.

Thanks for any clues.

Spark, fuel, compression, in that order.

 

[L34]

Spark at the right time also.

 

[Canyon Angler]

Thanks, Grizz55Chev and L34, that's the kind of thing I'm looking for.

Do plugs that visually look OK often quit? This one is a NGK...

If it turns out I have no spark, I guess I gotta pull the flywheel, yes? I was hoping not to have to get into it that far. Not sure I have a gear puller of the right size...

 

[Vintage Engine Repairs]

You sure you didn’t flood it? Lots of choking isn’t a good thing. You could have quite possibly just started it on the normal run position. Always try starting a recently used saw on run, maybe high idle, but not choke.

 

[Canyon Angler]

You sure you didn’t flood it? Lots of choking isn’t a good thing. You could have quite possibly just started it on the normal run position. Always try starting a recently used saw on run, maybe high idle, but not choke.

Thanks, yes, I tried to start without choke, and almost never use choke except on a cold saw (and only until it pops, when I switch lever to "run" -- I never use "half choke")... in this case, since it was sitting for an hour, I tried once or twice with no choke, then went back to "cold saw" routine. I guess it's possible I flooded it, but I sure did my best to clear out any flooding!

Watch, tomorrow, I'll have to come back here and eat crow...again...

 

[Stihl99]

By any chance were you underneath or near high electric transmission power lines?
I have seen many saws and weed eaters not start after running perfect if they sat turned off underneath transmission power lines for a brief time. The magnetic field screws up that equipment.

 

[HarleyT]

When you shut off the saw the last time, which direction was the bar pointed?

 

[HarleyT]

Seriously though, I would suggest you may have an older batch of fuel mix, and it was flooded by it.

Dry it out completely and buy some fresh fuel....

 

[grizz55chev]

Thanks, Grizz55Chev and L34, that's the kind of thing I'm looking for.

Do plugs that visually look OK often quit? This one is a NGK...

If it turns out I have no spark, I guess I gotta pull the flywheel, yes? I was hoping not to have to get into it that far. Not sure I have a gear puller of the right size...

When you shut off the saw the last time, which direction was the bar pointed?

Now, now Harley, they're serious.! I believe the man from down under is right, and the best way to clear a flooded saw is to crank the living zh!t outa it with the throttle held wide open, no choke till she pops off, your milage may vary.

 

[HarleyT]

I suggest doing such after emptying the tank, then after the flood has burned off, refill with fresh fuel and start over and see if it runs correctly after that.

 

[Canyon Angler]

Thanks, guys. The fuel was mixed yesterday, pumped from the gas station the day before that -- 90 octane non-ethanol, Mobil 1 2T Racing oil 40-to-1 with 2 oz of Seafoam added to 1 gallon.
Before that (for several months) the saw had been stored bone-dry (any time I store 2-stroke motors for a month or more, I run them dry, using choke to get the bowl as dry as I can).

Strangely, this was the same procedure I had followed with my 660 -- and that saw was a royal biotch to get started yesterday (I never had much trouble with the 660 before that) but once I got it going it ran flawlessly, and I didn't even have to adjust its carb. That 660 (muffler modded) runs like a raped ape.

Dollars to donuts says the 361 starts on the first pull this morning and makes me look like a dope again.

Omma guess you guys are pulling my leg on the high-tension electric lines and orientation of the saw when I shut down... (But TBH, I actually had been running the 361 upside-down shortly before shutting down, because I was cutting a notch to fall a tree.)

If I can't get it started this morning, I'll mix a new batch of fuel and use newer oil this time. (I have a sealed gallon of Motul 800 2T oil that I bought 2 yrs ago...the Mobil 1 2T is "slightly" older.)

Question: Now that I think about it, I suspect that "pouring some mix down the throat" can result in a saw that is FUBAR for a long time if the mix gets down into the crankcase, and could take a really long time to un-flood ... is that accurate?

 

[Canyon Angler]

Dollars to donuts says the 361 starts on the first pull this morning and makes me look like a dope again.

Question: Now that I think about it, I suspect that "pouring some mix down the throat" can result in a saw that is FUBAR for a long time if the mix gets down into the crankcase, and could take a really long time to un-flood ... is that accurate?

Well, I guess I get today's dunce award. It popped on the first pull, and 20 or so pulls after that, I got it to run. Apparently it was flooded, just as Tom and Harley and a few others suggested.

Thanks for all the helpful information (and patience). My 361 can be a royal PITA to unflood!

 

[HarleyT]

Power lines do affect your sperm count and testosterone levels though...
You have to be mindful where you point that thing.

 

[Bob Hedgecutter]

Years ago, both my local Husqvarna and Jonsered agents had a troubleshooting flow chart attached to the workshop wall. Must have been about 4 feet square and set out a bit like a year planner calendar- very cool chart and can help solve a mystery, save you missing a step and help plan a job before tearing the saw down. Guessing they were Electrolux supplied to agencies.

If you ever get the chance to grab a copy of these though, they are similar and easy to reference.

 

[Stihl99]

Power lines do affect your sperm count and testosterone levels though...
You have to be mindful where you point that thing.

Seriously,
Ok whatever seeing who this is coming from

 

[Canyon Angler]

Years ago, both my local Husqvarna and Jonsered agents had a troubleshooting flow chart attached to the workshop wall. Must have been about 4 feet square and set out a bit like a year planner calendar- very cool chart and can help solve a mystery, save you missing a step and help plan a job before tearing the saw down. Guessing they were Electrolux supplied to agencies.

If you ever get the chance to grab a copy of these though, they are similar and easy to reference.

View attachment 914045

Thank you!
Linky (thanks Google!)

 

[Canyon Angler]

Ok whatever seeing who this is coming from

I think Harley's sigline just got longerer!

 

[HarleyT]

I think Harley's sigline just got longerer!

Yeah, maybe.....

 

[tomalophicon]

This guide relates specifically to the Shindaiwa models but there is excellent information regarding troubleshooting and general 2 stroke information.
http://www.golftechs.us/Manuals/shin chainsaw_current.pdf