MS661C 2015 M-Tronic V3 4702A Coil Calibration Now Grenaded Piston

[stihl86]

If a CM saw is not "Calibrated" correctly or at all, the system will do it itself after about 45 minutes of fairly constant use.
With no damage to the saw. I never tried it.
The calibration, just like a carb adjustment, is critical when moving to a higher elevations.

Failure analysis is not an exact science. You have to rule out what didn't cause it.
The cause of the failure, is always what the guy who makes the final decision, says it is.
Looking at that piston, that damage didn't just happen. Its been self destructing for quite awhile.
And I'm sticking with a detonation theory LOL, because of poor quality fuel.
Not a system failure.

 

[Fatherwheels]

If a CM saw is not "Calibrated" correctly or at all, the system will do it itself after about 45 minutes of fairly constant use.
With no damage to the saw. I never tried it.
The calibration, just like a carb adjustment, is critical when moving to a higher elevations.

Failure analysis is not an exact science. You have to rule out what didn't cause it.
The cause of the failure, is always what the guy who makes the final decision, says it is.
Looking at that piston, that damage didn't just happen. Its been self destructing for quite awhile.
And I'm sticking with a detonation theory LOL, because of poor quality fuel.
Not a system failure.

The saw never ran right, and the net is full of people who had to change coils, and of different
versions of the solenoid, they weren’t introduced for nothing.

 

[DND 9000]

In the past there were reports about control units which were set up to lean. I don`t know if this is really true but the (4700 C and D marking on control unit) should be one of it. (The order part no. changed several times)

1144 400 4710 (C 2015)
1144 400 4720 marking on control unit 1144 4701 A (C 2017)
1144 400 4703 m-tronic v.3 from here on (C 2018)
1144 400 4704 marking on control unit 1144 4702 A (current version)

(C "year", last availible)

This could be a reason for this damage. You say your saw is built 2015? Also what is your serial number, would be good to know. There was also a change of the intake manifold and the cylinders. Do you have a Gilardoni cylinder?

 

[Fatherwheels]

In the past there were reports about control units which were set up to lean. I don`t know if this is really true but the 4700 C and D should be one of it. This could be a reason for this damage. You say your saw is built 2015? Also what is your serial number, would be good to know. There was also a change of the intake manifold and the cylinders. Do you have a Gilardoni cylinder?

Do Galardoni make good cylinders.

 

[DND 9000]

Yes normally. The plating on the Gilardoni cylinders of the MS 661 did not hold up, some guys said, therefore engine damage.

 

[Fatherwheels]

Yes normally. The plating on the Gilardoni cylinders of the MS 661 did not hold up, some guys said, therefore engine damage.

Not good news then, any idea if Stihl or Husqvarna use Galardoni of late.
I think I read where someone was modding a 590 and 620 echo and Galardoni
came up, no mention of problem though.

 

[DND 9000]

Not that I know. Stihl produces cylinders in their factory in Brasil now. Also the MS 661 has a "STIHL" cylinder now. It is also possible that they use cylinders from other manufactors across the complete product line.

 

[skygear]

In the past there were reports about control units which were set up to lean. I don`t know if this is really true but the (4700 C and D marking on control unit) should be one of it. (The order part no. changed several times)

1144 400 4710 (C 2015)
1144 400 4720 marking on control unit 1144 4701 A (C 2017)
1144 400 4703 m-tronic v.3 from here on (C 2018)
1144 400 4704 marking on control unit 1144 4702 A (current version)

(C "year", last availible)

This could be a reason for this damage. You say your saw is built 2015? Also what is your serial number, would be good to know. There was also a change of the intake manifold and the cylinders. Do you have a Gilardoni cylinder?

Yep. I had the 4700D coil in mine.

 

[PogoInTheWoods]

By the looks of the cleanup job you did on your cylinder, the plating certainly didn't seem to have any issues. Gilardoni typically makes a very high quality cylinder.

Time to look forward at how you're going to get the saw running again. What's done is done and your dealer has done little but waste your time. Even if you decide to go OEM with replacement parts, I wouldn't give them another freekin dime. Time to quit looking backward except maybe at what was in your fuel container before all this happened. All the other conjecture aside, you could have simply had a faulty piston that was destined to fail from day one. It happens. So upward and onward!

Again, though..., inspect the bottom end very carefully (if you haven't already) before going any further. If there is ANY roughness at all in any of the bearings, stop right there and sort it out before going forward. If you detect any slop in the big end bearing or there is severe heat discoloration at the bottom end, your repair bill just went up a lot from that 100 bux I suggested earlier. You'll probably need a crank. If the big end is solid and smooth with no discoloration, the same goes for the main bearings. There should be zero slop and they should be perfectly smooth or they'll need to be replaced as will the seals at that point. Easiest way to determine all of the above is to split the case for analysis and/or repair.

And don't think for one second that the MDG-1 software will tell a dealer or tech what caused the type of damage that you experienced..., or much else for that matter until you get to the 500i diagnostics . What it will tell you about carb saws aside from how many starts and some very basic stored info and some RPM numbers is...

"Might be the solenoid. Might be the carb. Might be the ECM, Might be all three, or any combination."

Hell, you already knew that before you walked in the door.

 

[DND 9000]

The damaged cylinders with the plating were in the 177... serial number range. Yours is higher.

 

[skygear]

By the looks of the cleanup job you did on your cylinder, the plating certainly didn't seem to have any issues. Gilardoni typically makes a very high quality cylinder.

Time to look forward at how you're going to get the saw running again. What's done is done and your dealer has done little but waste your time. Even if you decide to go OEM with replacement parts, I wouldn't give them another freekin dime. Time to quit looking backward except maybe at what was in your fuel container before all this happened. All the other conjecture aside, you could have simply had a faulty piston that was destined to fail from day one. It happens. So upward and onward!

Again, though..., inspect the bottom end very carefully (if you haven't already) before going any further. If there is ANY roughness at all in any of the bearings, stop right there and sort it out before going forward. If you detect any slop in the big end bearing or there is severe heat discoloration at the bottom end, your repair bill just went up a lot from that 100 bux I suggested earlier. You'll probably need a crank. If the big end is solid and smooth with no discoloration, the same goes for the main bearings. There should be zero slop and they should be perfectly smooth or they'll need to be replaced as will the seals at that point. Easiest way to determine all of the above is to split the case for analysis and/or repair.

And don't think for one second that the MDG-1 software will tell a dealer or tech what caused the type of damage that you experienced..., or much else for that matter until you get to the 500i diagnostics . What it will tell you about carb saws aside from how many starts and some very basic stored info and some RPM numbers is...

"Might be the solenoid. Might be the carb. Might be the ECM, Might be all three, or any combination."

Hell, you already knew that before you walked in the door.

I was told I would get a call today. Well, they close at 5:30pm. No call. So far.

I have invested in
2 pro backpack blowers
3 pro chainsaws saws
1 pro pole saw
1 pro combo unit with attachments
Plus all my oils, consumables and hand tools.

All from the same dealer. Never had any warranty work done or needed anything major besides bent pole shafts and minor things on the saws. Always purchased parts and done the work.myself.

Yes. I had already been making the plan to move forward. Inspected the lower end and it is buttery smoothe. Cleaned it out a little and was going to clean it 100% before it was reassembled.

 

[skygear]

The damaged cylinders with the plating were in the 177... serial number range. Yours is higher.

Thank you.. appreciate you looking into that for me.

 

[trains]

From whats been said, looks like a faulty solenoid, and thus poor fuel delivery has been the likely cause from the beginning.
I guess in future, replace solenoid along with coil, cheap insurance.
If it was my saw, I would be splitting the case, new bearings, and a good flush and inspection of the big end on the crank, lots of bits were shed, and will be all thru the internals.

Your this far in, do it well and do it once.

and a call into stihl going over your purchase history, and the issues and way you have been treated by your dealer would be worth while too.

 

[gary courtney]

Upgrading to V.3 was not the cause of the piston failure

You are correct ! I upgraded and did the calibration and runs excellent on my 661.

 

[Canyon Angler]

If this thread isn't a poster child for "don't buy a computerized saw," I don't know what is.

OP, I hope you get some relief out of Stihl USA, or at least get your saw to finally run right.

 

[stihl86]

By the looks of the cleanup job you did on your cylinder, the plating certainly didn't seem to have any issues. Gilardoni typically makes a very high quality cylinder.

Time to look forward at how you're going to get the saw running again. What's done is done and your dealer has done little but waste your time. Even if you decide to go OEM with replacement parts, I wouldn't give them another freekin dime. Time to quit looking backward except maybe at what was in your fuel container before all this happened. All the other conjecture aside, you could have simply had a faulty piston that was destined to fail from day one. It happens. So upward and onward!

Again, though..., inspect the bottom end very carefully (if you haven't already) before going any further. If there is ANY roughness at all in any of the bearings, stop right there and sort it out before going forward. If you detect any slop in the big end bearing or there is severe heat discoloration at the bottom end, your repair bill just went up a lot from that 100 bux I suggested earlier. You'll probably need a crank. If the big end is solid and smooth with no discoloration, the same goes for the main bearings. There should be zero slop and they should be perfectly smooth or they'll need to be replaced as will the seals at that point. Easiest way to determine all of the above is to split the case for analysis and/or repair.

And don't think for one second that the MDG-1 software will tell a dealer or tech what caused the type of damage that you experienced..., or much else for that matter until you get to the 500i diagnostics . What it will tell you about carb saws aside from how many starts and some very basic stored info and some RPM numbers is...

"Might be the solenoid. Might be the carb. Might be the ECM, Might be all three, or any combination."

Hell, you already knew that before you walked in the door.

The MDG is only another tool to “help”. As with code scanners for cars, they don’t tell you exactly what happened.
When I get a strange one, my dist will ask for the fuel numbers, then, with a great deal of secrecy, get back to me with which way we’ll proceed. I had just recently, two 661 wipe out cylinders. Serial numbers were very close.
One saw failed, the guy needed a big saw, bought another, that one fail quicker.
They told me to replace cylinders. Didn’t even ask about numbers.
That episode was placed on facebook by the owner of the saws.
Sometimes, the dealer is left in the dark. It’s not always his fault.
And he isn’t incompetent because he doesn’t have all the answers
But he should be damn sure of what he’s claiming is correct.
And also be able to and be willing to get those answers.

 

[angelo c]

In the past there were reports about control units which were set up to lean. I don`t know if this is really true but the (4700 C and D marking on control unit) should be one of it. (The order part no. changed several times)

1144 400 4710 (C 2015)
1144 400 4720 marking on control unit 1144 4701 A (C 2017)
1144 400 4703 m-tronic v.3 from here on (C 2018)
1144 400 4704 marking on control unit 1144 4702 A (current version)

(C "year", last availible)

This could be a reason for this damage. You say your saw is built 2015? Also what is your serial number, would be good to know. There was also a change of the intake manifold and the cylinders. Do you have a Gilardoni cylinder?

I have a newer 661 on my bench that's getting split and re-bearing-ed. DO you have a PN for the "seal kit" ? wondering if the "kit" is cheaper to purchase then the separate seals and case gasket sets ? Stihl is funny that way, sometimes it is..and some times it isn't ( cheaper to buy separately)

 

[skygear]

I have a newer 661 on my bench that's getting split and re-bearing-ed. DO you have a PN for the "seal kit" ? wondering if the "kit" is cheaper to purchase then the separate seals and case gasket sets ? Stihl is funny that way, sometimes it is..and some times it isn't ( cheaper to buy separately)

These? 1144 007 1600

 

[angelo c]

These? 1144 007 1600

thank you. looks cheaper then the seals alone

 

[PogoInTheWoods]

1144 007 1600 $24.73 US. A lot cheaper than the individual seals and gaskets which would run about fifty bux if purchased individually.