Does anyone else find the m Tronic saws seem to run lean?

ehp · December 18, 2021, 01:03:03 PM

Its moronic so it should set itself . The saw does not know if it's in 80f at sea level or at minus 40f at 10,000 feet above sea level so the mtronic takes care of that . As far as oil ratio goes I do what I like and want and have spent more than a few hours on a engine dyno doing 2 strokes and I have a computer dyno that is very accurate here at home . I use to run 20 to 1 shell XTC50 oil and that worked very good . Never had a single problem until the cutter mixed his own gas at 50 to 1 and he stuck the rings .

But the last bunch of years I'm running 40 to 1 klozt and zero problems and I mean zero and all saws are mtronic . Remember husky sent a bulletin out when the 385 came out to increase oil to 40 to 1 cause the saw was having so much crank bearing problems . Hell my dealer had so many short blocks in stock of new 385 just waiting to be replaced . .

What I have found is on moronic or auto tune saws are run it like you stole it right off the bat and first the rings seats faster and saw seems to work better to me . No starting problems like cranking 10 times like lots do . . I push my saws hard and ask alot of them .

Now this is no disrespect to the guys working on saws but if they are like the guys around here most have no clue to what's going on and you replace by part number and hope that fixes it . The old guys are retiring so it's not going to get any better in this field . It's a engine so use logic and figure it out . I got another saw dropped off just last night from a stihl dealer for me to figure out and I already know what they did and that took about 10 seconds . A 462 and guy running it burnt it up cause the chain saw super dull and just kept pushing on it saw has a new chain on it when dropped off but pretty easy to see how dull it was by the fine dust everywhere. Ext on piston is done and covered the rings

old guy · December 18, 2021, 06:31:31 PM

I have a550, 562 and 572, plug color is scary white on all of them.

ehp · December 18, 2021, 09:02:15 PM

Another guy I know just dropped off a 461 that he let a friend use . Saw has low hours and he said it does not have spark but as soon as I pulled the cord 6 inches I knew we had trouble . He dropped it off when I was at work but I pulled the cord when I got home . Cylinder is nice new color on outside but using 50 to 1 oil the crank bearings are history and a couple pieces came up threw the transfer ports . She is junk

ehp · December 18, 2021, 09:05:12 PM

He said he was using high test gas but who knows for sure but normally if a guy running low test gas from around here the cylinder will have a dark color inside and pretty much all our low test is at least 10% ethanol .

JoshNZ · December 18, 2021, 09:26:05 PM

Speaking in terms of stoichiometry only, if you run more oil and change nothing else on a carbed saw, you are running leaner.

Spike60 · December 19, 2021, 08:45:11 AM

I run 40:1 in everything. My thinking is the benefit of a little extra oil is for the bottom end more than the top end. Also figure it's better when I run my old saws. Never really thought of this as a big deal, and I'm surprised folks have such strong opinions on it. Difference between 40 and 50 is what? About 2 tablespoons of oil in a 2.5 gal gas can? Anybody really believe that adding that small amount of oil to a can of 50:1 means you have to go readjust all your saws?

The electronic saws are right where they are supposed to be. The RPM's are set by the saw making constant adjustments to maintain max rpm's under load. So, "lean" is a matter of perspective. If you like to run your saws a little fat, then the electronic saws would seem lean as they are always running on the edge. But that's no different than setting a saw for it's maximum rpm with a tach. Only the adjusted saw doesn't compensate for the variations that AT does.

What you guys want to keep in mind is that most of you know to adjust a carb, and therefore would rather do it yourself. That's fine, but out in the real world, most saw users have no idea how to adjust a carb properly. They usually just make things worse. Plus they often monkey with the carb screws on a saw that isn't running right when the actual problem has nothing to do with the carb. The result is often BANG!

HemlockKing · December 19, 2021, 08:49:45 AM

@Spike60 thanks for your thoughts. I guess I'll just keep doing what I've been doing and not worry..

kantuckid · December 19, 2021, 10:02:07 AM

Quote from: JoshNZ on December 18, 2021, 09:26:05 PM
Speaking in terms of stoichiometry only, if you run more oil and change nothing else on a carbed saw, you are running leaner.

You state carbed saw->"What about" my Stihl MS241 Motronic saw on more oil in the mix?
To your point (sort of ;D) it does of course have a carb, but wires slapped on the side of the carb body instead of adjustment screws.
Based on above comments, I should be running 40:1 in my saws, carbed and motronic both.

snobdds · December 20, 2021, 11:24:58 AM

I just run the $30/gallon gas in a can. It's actually cheaper in the long run.

I haven't had one blow yet and I am cutting at 6,500 and 10,000 feet respectively.

Dull chains are more of a problem on saws than oil ratio.

barbender · December 20, 2021, 04:49:50 PM

EHP, which Klotz oil are you running in your saws? I went to order some and there's lots of options.

JoshNZ · December 20, 2021, 04:54:15 PM

Quote from: kantuckid on December 19, 2021, 10:02:07 AM
Quote from: JoshNZ on December 18, 2021, 09:26:05 PM
Speaking in terms of stoichiometry only, if you run more oil and change nothing else on a carbed saw, you are running leaner.
You state carbed saw->"What about" my Stihl MS241 Motronic saw on more oil in the mix?
To your point (sort of ;D) it does of course have a carb, but wires slapped on the side of the carb body instead of adjustment screws.
Based on above comments, I should be running 40:1 in my saws, carbed and motronic both.

I have no idea how an mtronic works and what it's capable of sensing/adjusting but I'd bet it's a function of exhaust temp and won't run lean.
Strictly speaking, it'll have less power though xD. But yes I agree all of this is negligible.

snobdds · December 20, 2021, 05:14:10 PM

Quote from: JoshNZ on December 18, 2021, 09:26:05 PM
Speaking in terms of stoichiometry only, if you run more oil and change nothing else on a carbed saw, you are running leaner.

anyone who says you can burn the motor down by running too much oil to fuel ratio is out to lunch. Disregard anything they tell you. At a certain point the engine will no longer run, but it won't "burn down" or seize. You could end up with a lot of carbon in the engine, but it wont seize. Oil is the lubrication, it prevents seizing!

JoshNZ · December 20, 2021, 05:28:58 PM

Yep I agree. Didn't say you're gonna cook it but you're stoichiometrically leaner.

I don't think oil does anything for the top end temp though, I bet you can still cook your rings with a 20:1 oil mix if you're silly with the needles, hard to do your bottom end though. The evaporative cooling effect of fuel is what is in play when setting the mixture.

ehp · December 20, 2021, 07:56:56 PM

Bar . I run Klotz original techniplate . I only used this stuff when I use to make race fuel for alot of timbersport guys plus for myself and that was mixed with methanol and nitro methane and it was mixed at 6% oil of total volume . . Now I have seen motors so gummed up I could not get the cylinder off the crankcase but they were all running the maxium 929 or whatever the big crazy oil on the internet was 20 years ago . That oil just did not burn hardly at all . Another thing guys is the size of the ext outlet on the muffler which are pretty small these days on saws so that causes the heat from the muffler to stay in the cylinder and that makes the saws run leaner . Now if you opened up the muffler outlet you cannot let the engine get that white color cause it will burn down for sure cause now the heat in the cylinder is caused by running lean . The saw companies have the new Mtronic and autotune figured out pretty good as I'm very picky on how my motor runs as I have no problems . Now something no one has talked about is does more oil increase or decrease a engine horsepower if the carb is set correct and I have done that just to see on a dyno and a motor running 50 to 1 compared to same engine running at 16 to 1 , the only difference was the carb was set to run the heavier oil mixture and engine on average produced 8% more power on the 16 to 1

smoked · December 20, 2021, 09:53:52 PM

I think I remember reading here that increasing oil in the oil fuel ratio reduces octane so yo may risk detonation with more oil in the mix. I remember hearing pings in the old muscle cars when you cracked the throttle, but not sure I can hear it in a loud ass pro saw. I'd be careful going more than just a smidge outside whatever the OEM recommends.

barbender · December 21, 2021, 12:14:50 AM

I remember in our snocross race sleds, the Klotz would sometimes gum the exhaust valves up a bit, it was no big deal to pop them off and clean them. I'll have to order a jug, just for the smell and ol' times sake if nothing else😊

Now on the displaced fuel from a rich oil mix causing a lean air/fuel ratio. Ed's little experiment confirms to me what I suspected- that the 2 stroke oil is burning, as fuel. It's not just some neutral substance that displaces the gasoline, except maybe in the case of that Maxim or whatever the non-burning oil was. Man, Ed, 8%?! I might have to mix up a tank of 16:1, easiest mod ever😁

Ianab · December 21, 2021, 03:03:36 AM

Quote from: smoked on December 20, 2021, 09:53:52 PM
I think I remember reading here that increasing oil in the oil fuel ratio reduces octane so yo may risk detonation with more oil in the mix. I remember hearing pings in the old muscle cars when you cracked the throttle, but not sure I can hear it in a loud ass pro saw. I'd be careful going more than just a smidge outside whatever the OEM recommends.

Possibly true, but if you are running a higher octane fuel than the minimum, it shouldn't make enough difference to matter.
A performance car engine can knock if given full throttle at lower revs because the compression ratio is higher than normal, and it has the air intake to get a full charge into the cylinder. My old 1600 Toyota would ping at low revs like that, but it also ran 11:1 compression ratio and a throttle body that wouldn't have been out of place on a V8. ;) Now that engine was fussy about Octane ratings. Chainsaws, not so much

ehp · December 21, 2021, 06:10:38 AM

oil does not reduces octane, it depends on what oil your using as it may change what what spark timing you need to burn the oil in the gas just like stuff like nitrous as oil will increase the cylinder pressure but on most saws its a non issue as the motor is pretty crude in design . , now on the klotz , they make alot of different oils and alot of dealers will want to sell you the newer designed oil but you have to run that oil at a higher ratio as it will gum your motor up , the stuff I'm using I go threw cases of it a year but its not cheap but I have never lost a crank bearing or a piston and I run my stuff pretty hard

Real1shepherd · December 21, 2021, 11:42:28 AM

Quote from: Spike60 on December 19, 2021, 08:45:11 AM
I run 40:1 in everything. My thinking is the benefit of a little extra oil is for the bottom end more than the top end. Also figure it's better when I run my old saws. Never really thought of this as a big deal, and I'm surprised folks have such strong opinions on it. Difference between 40 and 50 is what? About 2 tablespoons of oil in a 2.5 gal gas can? Anybody really believe that adding that small amount of oil to a can of 50:1 means you have to go readjust all your saws?

The electronic saws are right where they are supposed to be. The RPM's are set by the saw making constant adjustments to maintain max rpm's under load. So, "lean" is a matter of perspective. If you like to run your saws a little fat, then the electronic saws would seem lean as they are always running on the edge. But that's no different than setting a saw for it's maximum rpm with a tach. Only the adjusted saw doesn't compensate for the variations that AT does.

What you guys want to keep in mind is that most of you know to adjust a carb, and therefore would rather do it yourself. That's fine, but out in the real world, most saw users have no idea how to adjust a carb properly. They usually just make things worse. Plus they often monkey with the carb screws on a saw that isn't running right when the actual problem has nothing to do with the carb. The result is often BANG!

Agree....I was running Stihl Ultra @50:1 in everything and then changed back to 40:1. No real reason or evidence to do so. I was just thinking about all these old saws and the investment of $$$ and time. I figure it's a smidge more insurance, if anything at all.

If one of these old saws lets go, it won't be from the oil mix. Peace of mind more than anything. But then, I never had any carbon issues @40:1 and I check periodically. I tend to run on the pro use lean side, always have. NOT recommended for homeowner saws.

Kevin