Stihl MS 461 won't start - it's ~8 months old

[tburch]

Before you start throwing out suggestions - just know that I dropped it off at the repair shop this morning.

A few months back (April) I used it during a rainstorm to remove a fallen tree off a fence.  I used it for about a hour, sometimes the rain was really heavy. 

That day, and most every time I had previously used it, it started on the 1st or second pull.   

About 8 weeks ago, I used it to cut some slash into firewood-sized pieces.  I don't recall if it was hard to start. 

About 6 weeks ago, it took about 20 minutes to get it started.    Last night, after about 100 pulls, it never started.   I don't used it THAT much, as you can see.

I've been using premix from the same dealer I bought the saw.   When I was trying to start it, I smelled fuel, so it was flooded.  I let it sit, tried again, and that didn't help.

When I was at the repair shop this morning they did a quick triage on it, and told me "you flooded it".  I said "I didn't flood it - it flooded itself".  He pulled the plug and put a new one in.  Nothing.   They decided to check it in to further look at it. 

I hope it's nothing major.  Anyone else had any issues with this caliber saw not starting within the warranty period? 

[joe_indi]

When you were pulling those 100 times on the starter was it on choke?
It the answer is a yes, you have mighty big flooding at hand.
Remove the spark plug, have the MC lever on O and hold the throttle wide open with the saw upside down.
Pull the starter about 8 - 10 times (was any fuel dripping down?)
Now dry out the spark plug and refit it. Have MC lever in Start (one step above Choke) and pull the starter..
If everything else is ok the saw should start.
If it does not start, in your place the next thing I would suspect is the ignition module. The 461 module with its electronic advance and speed limiter as the habit of going bad without any reason.
 The only way to check is to install another working ignition module.
Even one from a 460 will do for this test.

[tburch]

I always initially start with the choke on.  After the first fire, I set it to 1/2 choke. 

But, all 100 pulls were not with the choke on.  Most times, the choke was not on at all.   I did not attempt to pull the plug to do your regiment, but a  good suggestion.  The repair center essentially did that though, and it still would not start. 

I just called the repair center and they hope to get to it today.   Yeah… me too. 

[CrufflerJJ]

My MS250 always flooded easily.  Like you, I'd put it on full choke & pull until I heard the first pop, then would move the lever to half choke & pull till it started.

The problem is that you may not hear a "pop" before you've flooded the engine.  I was told by my local Stihl tech to pull it only 2-3x on full choke, then change it to half choke.  This seems to work for me.

On their website, Stihl also seems to agree with this approach.

http://www.stihlusa.com/faq/products/chainsaws/

A good rule of thumb to follow is to remember that when placing the switch control to the full choke setting, more liquid fuel and less air flow into the combustion chamber in order to create a higher chance for ignition. Pulling the rope more than two to three times in this setting may flood the engine. The operator should move the Master Control Lever™ or choke lever from the full choke setting after three to four pulls even if the engine does not fire. Moving the lever to the next setting, the half choke or part throttle position will allow more air into the combustion chamber and help resolve the flooding condition.

[Thehardway]

^^^^ this ^^^^ and, it might be that you got some water in your fuel on that day you were cutting in the rain.  Anytime my saw won't start cold with a dozen pulls or less, I dump that gas in the tractor and mix up some fresh.  Saw runs better on fresh fuel anyway.  It only takes a small amount of water in the fuel to make a cold saw nearly impossible to start and if you do get it started, it will stall often or idle poorly in my experience.  Today's fuels are really bad about absorbing water.  Anything premix  opened longer for than a month will be suspect for moisture or poor performance.

[tburch]

Great tips!   

I called the saw shop again.  Now they tell me they'll look at it first thing Monday.   I'm not holding my breath. 

[tburch]

Got my saw back.  Diagnosis - they said it was just flooded. 

Interesting because I tried using the saw on Wednesday evening.  Took the saw in on Thursday morning and they could not start it either.  The compression release button was pushed in from Wednesday eve -> Thursday morning, and they also took the plug out (swapped it out) Thursday and blew the cylinder out, and they still could not start it. 

I'll try it this evening to see what it will do, using the above process to avoid flooding.  (Actually, I'll try to start it without the choke first.) 

[altimports]

Have you had any further issues with your saw?

I have a 4 month old MS 461 that has worked faultless. It has only used Stihl premix to keep the saw in perfect condition. Currently it has used about 6 tanks since new.

Yesterday I fell a large tree at the base, the only cut for the day. Came back about an hour later to chop the tree up and the saw would not start, tried everything. This morning I tried again and nothing. It is now at the shop for inspection.

I am concerned this might be an ongoing issue/fault the saw or the premix fuel.

[joe_indi]

One of the few unreliable components on the 461 is the ignition module. And there is no way of running any tests on it.
The only way to verify a suspect coil is to do the traditional fool proof method, a coil swap. Ok getting another 461 coil at short notice might be near impossible. But how about one from a 460,or a 660, or even a 290 or a 390? Any of these will work on a 461. So IMHO first confirm the coil is working before going any further

[Texas-Jim]

A flooded two stroke can be a pain, its not just theres a bit more gas in it. The piston has gas in it, the crankcase is full of gas. They can be a bear to start. But saws flood for reasons, many tiomes its the user but it can be a failure,,as in ignition or even a carb problem. Best way imo is, 1~ to not use compression release if you can pull it easy without it, 2~three pulls max on choke, 3~ if it has not started in a max of ten or twelve pulls just quit. It has a problem that needs to be found. Last everyone that works on small engines needs one of these, it can make your life easier. It removes the ignition worry from a non starting engine. EBAY AD REMOVED BY ADMIN, SEE RULES Thats an example you can buy one from any stihl dealer as well.

[joe_indi]

I use a ZAT 3. But it is limited to only testing whether the ignition is putting out a strong enough charge of electricity to produce a spark. It will not ascertain whenthat spark is being produced, whether it is at the correct timing.
This is what Stihl's workshop manual says about this:
"However, an internal fault in the
circuit can alter the switching point
in such a way that a spark test will
still show the system to be in order
although timing is outside the
permissible tolerance. This will
impair engine starting and running
behavior."
The only way round this is to test the saw with another suitable ignition module, or, try another saw with the ignition module of this saw.

[PNWRusty]

I've never tried a strobe style timing light on a chainsaw but...why wouldn't that verify proper timing without needing another compatible saw to test it (only a 12V battery)?

Maybe I'm just not thinking clearly.

[Texas-Jim]

Joe thats true it can only indicate that it has a spark. But in my experience a ignition module failure is complete or heat induced. Meaning when it gets hot it fails, even that is rare considering the way modules are made. Iv never had one alter the timing even though its theoretically possible.

[joe_indi]

Jim, while module failures are rare, I have seen it happen on certain models
Brushcutters that had the module mounted on the cylinder, with speed limiter or ignition advance circuitry (FS 85, FS55 and early 4Mix engines of FS100 and FS130) Probably from thermal overload.
Husky 372XPs of a decade ago, those that had speed limiter coils (blue coils)
MS461s are the ones I have seen recently with failure.
I dont know the reason, maybe from the speed limiter working continuously due to low load and high revs. Users tend to run a lot on blunt chains here and the common bar size is 18".
Some some customers who are prone to over revving I trim off the third pole (that works the limiter and advance) as a precaution, and those saws run without any problem.
But some customers prefer a coil swap.

[ZeroJunk]

I've never tried a strobe style timing light on a chainsaw but...why wouldn't that verify proper timing without needing another compatible saw to test it (only a 12V battery)?

Maybe I'm just not thinking clearly.

There is a You Tube video of a guy doing exactly that. He made a mark on the crankcase and flywheel at top dead center with a magic marker. He started it with the screws out of the starter cover and took the cover off once started. He may have made a second mark where the saw was firing at idle. Anyhow , he was checking to see how much advance it had as it was revved up. So yeah, you can do it.

[khntr85]

So how is the saw running now....only had my 461around 2-years, butbit has without a doubt been dead so far!!!

  I have realized something over the past few years as I have worked on and rebuilt more and more saws....ALOT of people don't know excactly what the "pop" is....every single person that has brought me flooded saws, pulls way to many times on full choke....I have had all these guys show me how they try to start their saw and evertimebthey miss the "cough".....these guys are thinking that the saw should run for a few seconds on full choke, wrong!!!

 I have just found the best thing to tell these guys is this... pull the saw 2-3 times on full choked no more...

[tburch]

Saw has worked fine ever since.  I've have been much more judicious with the choke since then.   When warm, I never choke it now.  When cold and full choked, as soon as I hear it sputter, I move it to 1/2 choke and never go back to full choke.   If warm, I don't compression release it either.

Great saw.  Small learning curve on starting it.

[nitehawk55]

Remember , Stihl has a life time ignition module warranty

[joe_indi]

Today I had a MS461 come in with erratic running.
All I had to do was saw off that third pole.
Okay, it no longer has auto ignition advance or rpm limiter, but the saw is running smooth now.
Here is a picture of what I did.

[PNWRusty]

No more ignition advance? Won't that reduce cutting performance and make it drink more fuel?