Well I still feel like I took $1400 and set it on fire this summer. I did get about 60 hours of use out of this saw, and now it is back on the shop, approaching a month now. I had hoped to get the problem all figured out to share with anyone else trying to diagnose one of these machines. But apparently, no one can.
When I deleted the muffler screen and started running the saw I was quite content. I didn't really think about the implications of this - not in terms of the future of running the saw, but what could cause a muffler screen to be completely plugged before the engine had even the first gallon of gas run through it? Surely that can't be the way the design works, here in the 4th year of this model #.
I would note that the first gas in this saw was a can of Stihl's own 'MotoMix', so I didn't start with some bad fuel and go downhill from there. After that it was 91 Octane No-E "Rec" Gas + Stihl HP Ultra, from the most popular gas pump in my town. No one has complained about the quality from that pump that I am aware of.
I think the vibration was coming from the engine, as it was the same when making a long difficult cut - maxing out the capabilities of the engine. Except this was happening even at idle sometimes, before the muffler screen delete. The idea that it was the gearhead or the shaft was a dead end, I believe. I offered to buy the gearhead the distributor sent out; won't be bad to have a spare and I have heard these aren't as likely to last as long as Husqy's do - and perhaps not as long as the engine will last. But I can't buy a spare part, yet, for a saw that doesn't work, yet.
But off to work I went. I prefer to give a brush saw to a new hire, to start learning the physics of cutting wood with a safer machine than a chainsaw. I had a lot of work on a 5" diameter maximum and this saw should be perfect for that application.
Of course, the kid running the saw quit soon enough, as 21 year olds are wont to do, after about 50 hours on the clock altogether. I was really looking forward to running it myself anyway, to get away from 2 tanks of brush-saw : 1 tank of chainsaw, using the chainsaw on the 4-5" Hard Maple and Ironwood. I picked up the saw one morning and away I went, until about noon, when the saw started running very raggedy.
I checked the plug and it was completely fouled. Duhh-huhh, whatever problem plugged up the muffler screen (super rich exhaust) would probably foul a spark plug too. I should have realized this but I spend more time on the logistics of working far from home than the fine details of the saws sometimes. I shouldn't have to even think about a saw that doesn't have even 100 hours of use on it, and I have plenty to think about with 4 other worn-out brush-saws.
I replaced the plug to see what would happen. The new plug couldn't get through the first quart of gas in the engine before it was plugged too.
When I got home, I dropped it off at the dealer. Once again, the company rep who "knows these saws well" was not available for a week, just my luck. I called the other day and the dealer was just then finally going to bring in a new laptop to run the Stihl diagnostic software and see what is happening. It sounded like he didn't have a computer that could run the software on hand yet, three weeks after I gave him the saw back. He thought this would be like doing a "hard reset" on 'The Module' (is there a better technical term for the computer chip that controls the fuel in this saw?), which would clear up any issues, and would call me the next day.
But that never happened. I am leaving on Monday for four months out-of-state, including some cutting jobs, and can't take this saw with me now.
So I turn to you all once again, for ideas on what to discuss with the company over the winter.
My current idea is that probably it has a bad carb. Let's say one of the jets in the carb wasn't manufactured as perfectly as 'The Module' thinks it is. If the jet then releases a different amount of fuel than The Module thinks, I don't see any way in the design that The Module could compensate for that. Basically, there is no O2 sensor reading the exhaust as there is on a fuel injected vehicle engine. Unless I am wrong on that, would like to know.
I already told the dealer all that - just put a new carb in it. (He is testing it with a brand-new muffler screen; I could use a torch to clean the original screen but I told him I didn't think I should have to carry a torch around with me to clean the screen twice a day.) But of course they seem to be resisting the carb idea as well.
I guess my main question is - have there been any other examples of an M-Tronic saw from Stihl that just would never run right until the carb was replaced?
The other problems possibility is whatever sensors do exist in "The Module", which I believe is a simple sealed unit. When I first priced one of these saws, I asked a dealer the price on a spare Module. He couldn't figure that out, and told me I would never need one. Uhh-huhh.
Oh and someone mentioned in another thread I read that individuals can get their own copy of Stihl's M-Tronic software now. Is this true? I'm fairly sure that is not an option from Husqvarna.
When I deleted the muffler screen and started running the saw I was quite content. I didn't really think about the implications of this - not in terms of the future of running the saw, but what could cause a muffler screen to be completely plugged before the engine had even the first gallon of gas run through it? Surely that can't be the way the design works, here in the 4th year of this model #.
I would note that the first gas in this saw was a can of Stihl's own 'MotoMix', so I didn't start with some bad fuel and go downhill from there. After that it was 91 Octane No-E "Rec" Gas + Stihl HP Ultra, from the most popular gas pump in my town. No one has complained about the quality from that pump that I am aware of.
I think the vibration was coming from the engine, as it was the same when making a long difficult cut - maxing out the capabilities of the engine. Except this was happening even at idle sometimes, before the muffler screen delete. The idea that it was the gearhead or the shaft was a dead end, I believe. I offered to buy the gearhead the distributor sent out; won't be bad to have a spare and I have heard these aren't as likely to last as long as Husqy's do - and perhaps not as long as the engine will last. But I can't buy a spare part, yet, for a saw that doesn't work, yet.
But off to work I went. I prefer to give a brush saw to a new hire, to start learning the physics of cutting wood with a safer machine than a chainsaw. I had a lot of work on a 5" diameter maximum and this saw should be perfect for that application.
Of course, the kid running the saw quit soon enough, as 21 year olds are wont to do, after about 50 hours on the clock altogether. I was really looking forward to running it myself anyway, to get away from 2 tanks of brush-saw : 1 tank of chainsaw, using the chainsaw on the 4-5" Hard Maple and Ironwood. I picked up the saw one morning and away I went, until about noon, when the saw started running very raggedy.
I checked the plug and it was completely fouled. Duhh-huhh, whatever problem plugged up the muffler screen (super rich exhaust) would probably foul a spark plug too. I should have realized this but I spend more time on the logistics of working far from home than the fine details of the saws sometimes. I shouldn't have to even think about a saw that doesn't have even 100 hours of use on it, and I have plenty to think about with 4 other worn-out brush-saws.
I replaced the plug to see what would happen. The new plug couldn't get through the first quart of gas in the engine before it was plugged too.
When I got home, I dropped it off at the dealer. Once again, the company rep who "knows these saws well" was not available for a week, just my luck. I called the other day and the dealer was just then finally going to bring in a new laptop to run the Stihl diagnostic software and see what is happening. It sounded like he didn't have a computer that could run the software on hand yet, three weeks after I gave him the saw back. He thought this would be like doing a "hard reset" on 'The Module' (is there a better technical term for the computer chip that controls the fuel in this saw?), which would clear up any issues, and would call me the next day.
But that never happened. I am leaving on Monday for four months out-of-state, including some cutting jobs, and can't take this saw with me now.
So I turn to you all once again, for ideas on what to discuss with the company over the winter.
My current idea is that probably it has a bad carb. Let's say one of the jets in the carb wasn't manufactured as perfectly as 'The Module' thinks it is. If the jet then releases a different amount of fuel than The Module thinks, I don't see any way in the design that The Module could compensate for that. Basically, there is no O2 sensor reading the exhaust as there is on a fuel injected vehicle engine. Unless I am wrong on that, would like to know.
I already told the dealer all that - just put a new carb in it. (He is testing it with a brand-new muffler screen; I could use a torch to clean the original screen but I told him I didn't think I should have to carry a torch around with me to clean the screen twice a day.) But of course they seem to be resisting the carb idea as well.
I guess my main question is - have there been any other examples of an M-Tronic saw from Stihl that just would never run right until the carb was replaced?
The other problems possibility is whatever sensors do exist in "The Module", which I believe is a simple sealed unit. When I first priced one of these saws, I asked a dealer the price on a spare Module. He couldn't figure that out, and told me I would never need one. Uhh-huhh.
Oh and someone mentioned in another thread I read that individuals can get their own copy of Stihl's M-Tronic software now. Is this true? I'm fairly sure that is not an option from Husqvarna.
