Stihl 462CM Hard Cold Start

thecfarm · April 15, 2021, 06:48:07 AM

Quote from: YellowHammer on April 14, 2021, 07:38:36 AM
I'm going to try the slow pull throughs today, until I can smell fuel, maybe a half dozen or so.

I do the slow pull on my 372. Makes a big difference on when it will fire with the chock on. But I only pull it over 3 times. I've tried more, but that seems to flood it. Seems like to me 3 is the magic number for me.
Just want to give you a heads up that. Mine is an old 372. And I also have found out the 372 will start much better at 40-50° than when I leave it in an unheated garage. Just a light bulb and an old piece of carpet will warm it up and help on the cranking part. But I do know where you live too. ;D

YellowHammer · April 19, 2021, 11:34:42 PM

Well, things have changed dramatically. My saw, which I fondly call "Ol Ten Pull" is magically "healed" and is night and day different. The problem is I have absolutely no idea what did it, but it has started first pull cold for a couple days in a row, and this morning I did a three pull slow roll and it started first full pull, again. The only thing I can think of is that somebody robbed me, took my other saw, and replaced it with a different one. :D :D

Actually, I went to the Stihl dealer who would not work on my saw because I didn't buy it there and cornered the mechanic who had me do a couple things like pull and reattach a couple wires I hadn't messed with before, one set of which I actually heard "pop" in place. That could have been the problem. I bought a new spark plug (the second one), air filter and fuel filter, and noticed when I was installing the fuel filter that the original one wasn't all the way on the fuel line. So made sure the new one was. Then I replaced the oily air filter which was only 3.5 months old.

At that point I pulled the starter and the stupid saw cranked up and ran on the very first pull. You could have knocked me over with a Vienna Sausage.

mike_belben · April 20, 2021, 12:19:26 AM

Pop as in electrical pop.. An arc?

thecfarm · April 20, 2021, 05:30:39 AM

That is good news!!

customsawyer · April 20, 2021, 07:07:28 AM

My 462 problem is different. It starts normally by the second or third pull cold but when hot that is where my problems come in. Sometimes it does fine and sometimes it takes 20 pulls. If it's in the 20 pull mood then when it does fire it won't stay running. It just about went in the burn pile the other day.

YellowHammer · April 20, 2021, 07:10:33 AM

No, as in it hadn't been seated all the way mechanically and so maybe not have been seated all the way electrically, either. It looked like it was fine, so I started tugging on it hard, (and all the other wires I could do get my hands on) trying to see if the wires would come out of the connecter, and something didn't look right, so I pushed the halves together and heard the "snap" of the connector closing all the way with the the other side. So I don't think the connector was seated correctly. Maybe, but I'm not sure.

I also pulled all the air cleaner stuff off and tightened the carburetor mounting nuts and they were a couple turns from tight. They weren't rattling around loose, but they weren't what I'd consider tight enough to get a good gasket seal. Again, I don't knowing it was an issue, but it sure isn't now.

As I mentioned, the fuel filter was seated all the way in the little plastic hose, and wasn't getting a good seal, but again, maybe it was.

Either way, when I put the whole thing back together, I resigned myself to pulling on it until my back hurt, and lo and behold, I ran on the very first pull. I shut it off and put it in the shelf, and the next morning, went out again, and it fired up in the very first pull.

The next morning, it didn't fire on the first pull but did on the second.

The next day I slow rolled it a 3 times as indicated by the other posts, and it started in the first real pull.

I don't know what's going on, but I may have to rename it from "Ol Ten Pull". :D :D

doc henderson · April 20, 2021, 08:15:21 AM

great news! Jake, yours is more like mine was (261 and a prev. 661) and acted like it was flooded and would not start warm. It would start 9 times out of 10, and always at the dealer. I returned the 661 and got the 880. they replaced the metering solenoid and the 261 has been fine since.

thecfarm · April 25, 2021, 06:53:31 AM

I always slow pull my 372. That makes a big difference on how it starts. Use to take 6-7 hard pulls to get it started.
Glad you found the problem.

YellowHammer · April 25, 2021, 09:05:22 AM

Old "Ten Pull" still starts first or second pull. It's really a fine saw, snappy and strong. I use it everyday.

I have no idea what fixed the problem, maybe it overheard me on the phone calling my dealer asking what I could get for trade it. Maybe that scared it... :D :D :D

realzed · April 26, 2021, 08:04:57 AM

Quote from: ehp on April 14, 2021, 10:55:44 AM

No its a fuel problem . Lots of weed wackers have the same problem with the screen in the carb getting plugged solid of a very fine red dust . One fuel brand is by far the worst and lawn guys that do it for a living pretty much every 2 weeks get that screen cleaned as they run them 50 plus hours a week .

Care to pass along your 'one fuel brand' findings - or at least how your experience has taught you the pecking order from worst to best?
If there is a difference between them and one, or even a few of them specifically seems to be at fault and avoided, it would certainly be nice to know!
I have always used Shell (best grade) as the station local to me is the sole one that seems capable of assuredly and consistently telling me that their highest grade 91 octane stuff is ethanol free - at any of the other stations I mostly just get blank looks or obvious lying answers to my question..
Thanks!

thecfarm · April 29, 2021, 06:15:15 AM

I use the highest grade of fuel at my local gas stations for all my small engines.
I use the high grade for my small Chevy truck. Started out with regular, did not run good at all. When to the high grade it got much better, but still not really right. Went there once at lunch and they was changing clerks and had to count money and nothing could be sold until they got done. I was close to being done for lunch so went up the road and got the high grade gas. Seem to run much better. Next fill up I went back to the one I always go to. Back to not running good again. Went back to the one I did not go too and it ran better. So I went back to the one I always go to, Same thing, running bad again. That just about proved it, I do not get high grade there anymore and the truck is running great!!

realzed · April 29, 2021, 03:09:40 PM

I'd still like to know what brand of fuel Ed considers is the worst that he mentioned since I'm not that far away and probably have the same brand choices that he has to choose from!
But I'm sure each individual station has underground tanks that hold fuel - some better or less 'contaminated' than others..

realzed · May 10, 2021, 04:57:23 PM

Guess I'll never know...

YellowHammer · May 21, 2021, 09:06:42 AM

A couple things to add to this. The 462 is still running fine, and recently I ran a can of pre mix through it, as an experiment, that I bought from my local chainsaw store. Ehp was right, that stuff is like canned dynamite in a chainsaw. It was surprising how much the saw liked it.

I was impressed, to say the least. I'd like to know what is in it, the jug says 94 octane no ethanol plus a synthetic two stroke oil. So why does the fuel I use, bought from a local pump, not work as well? It's 93 octane no ethanol, with Stihl 50:1 oil? What is the difference? What else do they put in the pre mix that makes a saw perform so much better than my best top of the line pump gas and oil?

To test it, after a couple tanks, I went back to the 93 octane no ethanol pump fuel/Stihl mix and could immediately feel a difference. This has really got my curiosity up.

From another standpoint, amongst all this, my Stihl dealer got in a new shipment of 500i's and one followed me home. So it was time for the acid test. Pour in my pump gas &Stihl oil mix into the saw, hit the primer button a few times, pull the rope 2 times, (never been cranked before) and the saw comes to life. Wow. Sweet.

btulloh · May 21, 2021, 09:18:04 AM

Good question YH. I've been wondering the same thing. Is there a FF member with a gas chromatograph?

mike_belben · May 21, 2021, 03:57:51 PM

Two thoughts on this.

First is, if the Mtronic computer uses a knock sensor then it can probably advance the fuel and ignition timing curve up until just before knock (detonation) in order to make more cylinder pressure and thus torque.

2nd one is, in my racecar days one of my mentors who has passed on was a guy named don who catered to the dyno queen crowd. Don had a vague man of mystery persona but was well known for laying down HP and his customers had the screenshots to prove it.

Don was one of several who took me under their wing and one day on the phone he said to me the secret is in the fuel. If i wanna make another hundred horse i just call VP and say blend me up another hundred horse. Add the right fuel blend and you just keep going up on the boost, up on the ignition advance and spraying more fuel and making more power.

When i got out of hondas 18yrs ago 1,000hp and 9s was the whoa line. 2 years ago speedfactory was at 2000hp from a 2.0L 4 cylinder @85psi boost. Running 7.7's @ 210mph in a front wheel drive manual trans to boot. Now all motor engines are making what turbo engines used to. 10k rpm on stock cranks.

Fuel and timing.

nativewolf · May 21, 2021, 05:11:31 PM

On these days when we are getting 40 degree temp swings the pump gas killed me. I can't even get 93 non ethanol.

A colleague uses 87 non ethanol then the syth oil then an octane boost. By the time we do all that we might as well buy the pre mix is what we decided. So we bought a pallet to save 30%. A bit more than fuel and oil and octane mix but not much. The saws do run better and 25 5 gallon jugs hold us and that saves some $ in time going to the store.

Real1shepherd · May 22, 2021, 12:15:27 AM

'Aspen' fuel is some pretty great stuff, but not a NA product AFAIK. The farm store type non-ethanol and the premix stuff has got some nasty ingredients....especially when you consider the price you're paying. Not saying it won't run well in your saws, but it's incredibly spendy.

I'll just continue to use pump non-ethanol and Stihl Ultra......

Kevin

doc henderson · May 22, 2021, 10:51:32 AM

I went to the trouble of getting aviation fuel. no alcohol, high octane (100) and have been using it. gone through about 5 gallons. not sure if it makes a ton of difference, but better on the carb parts I would think.

realzed · May 22, 2021, 10:39:08 PM

I too use 100LL and mix it with 91 non ethanol pump gas mixed about 50/50 or a bit higher on the av stuff..
The price for avgas here isn't all that bad compared to the best pump gas I can get my hands on so why not, and I know the shelf life is far better than any service station crap available here as well?
I also mix it at 40:1 mixture along with Stihl synthetic oil and my 261CM seems to like it just fine over most anything else I've tried - so I'll stick with the combo..
The Stihl or Husky canned stuff 94 and 95 is good and like the av gas combo I can actually hear the difference when the saw is on it - but it's too pricey for me!

YellowHammer · May 23, 2021, 12:05:00 AM

I don't recommend avgas in a chainsaw. It's much better to use autogas.

Several years ago, when I was doing advanced engine testing on high performance aircraft engines, we ran quite a few different types of fuels through high air cooled piston engines and evaluated them through a series of federal air worthiness tests.

Interestingly enough, Low Lead Aviation Gas has a quite high lead content as compared to conventional low lead automotive fuels. The very substance that is added to it, Tetra Ethyl Lead, to increase its octane levels can cause severe lead fouling in cooler running engines, those which which operate at less than 1,650°F cylinder head temperatures. After lengthy runs, the uncombusted lead would precipitate on the piston cylinders, the heads, valves, and even the spark plug as a whitish powder or a gravel "clinker". (No I didn't make the term up, search Google for Avgas, Clinker, lead deposits.) This whitish gray crusty deposit had the effects of causing preignition, loss of piston clearance, and even spark plug bridging and shorting. At some point, the clinker would glow hot enough to even cause dieseling or knocking, (pre ignition) which quickly destroyed the engines. This lead fouling, or clinker deposit can cause a shorten life of the engines, and is especially troublesome in high compression, small, carbureted, air cooled piston engines, such as the ones we were evaluating. Or any engine that doesn't maintain relatively high cylinder head or turbine temperatures which would help combust the ethylene dibromide, which is added by the fuel manufacturer as a lead scavenger. This is lead fouling is a known problem in the aviation industry, and is one reason that engine manufactures are so strict on their engine warm up, run up, and cool down procedures. Did you ever wonder why aircraft engines typically leave a brown or black exhaust streak that stains the aircraft wing? That's remnants the combustion byproducts of the ethylene dibromide scavenging off the tetra ethyl lead. If the engine was run too cool, that gunk stays in the engine.

Also, there are several additives that can be used to minimize the clinker formation.
Decalin is a good example, but the generally accepted best is tricresyl phosphate, or TCP.

Probably the best known, although generally long forgotten for that purpose, is Marvel Mystery Oil, which was used as far back as WWII to prevent lead fouling of bomber aircraft engines. It is still used today.

We worked with several of the major fuel companies to mitigate these issues, and it was a fun project. We blew up LOTS of engines. Here are a few quick references if you are interested.

https://www.shell.com/business-customers/aviation/aeroshell/knowledge-centre/technical-talk/techart-18-30071600.html

https://www.pipercubforum.com/marvel.htm

Real1shepherd · May 23, 2021, 11:15:24 AM

When I was working in the woods, leaded premium was still available. Some used it in their saws....the Swedish saw manufacturers were against it. They said it would cause the saws to run hotter because of the increased octane.

I never had a dawg in that fight so I just used reg leaded gas. Then, as they were phasing out leaded gas I just switched over to reg unleaded gas which was around 89 octane then. Now here, non-ethanol premium is about 91 octane. Premium therefore, is close to what reg non-ethanol used to be. I'm betting if you used an IR gun on the cylinders of saws run on AV fuel against saws run on non-ethanol pump gas....the AV fuel saws would run hotter. Anyone want to try that experiment?

When I was using leaded gas in chainsaws there was no particular coke or carbon problem...or "clinker". More important was getting your oil mix right for your saw and working conditions.

If you took the valve covers off car/truck engines run on Tetraethyl lead, you could see the lead deposits. Not a bad thing because the lead lubricated the valve train. Rebuilding car/truck carbs you could see the red deposits all inside your carb.....that was supposed to be the concentrated Tetraethyl lead.

Kevin

YellowHammer · May 23, 2021, 12:59:00 PM

Basically, what I'm saying is that aircraft engines have their fuel optimized specifically for them, and likewise, automotive engines have their fuels optimized for them. Boats utilize marine fuels specifically blended for them, also. As a practice, (people can do what they want) I put marine fuel in my boat, auto fuel in my car, and if I owned one, my airplane would get aviation fuel. Maybe I should also be feeding chainsaw fuel to my chainsaw, because it certainly seems to like it.

As with most things, the optimization of the fuel blend is a tradeoff based on its intended application. Thats why I'm interested to know what is in the premixed chainsaw fuel, I'd like to know what additives are involved, and if it has the effect of improving apparent performance while reducing engine life. Or maybe it will increase engine life. I don't know, thats why I ask.

Does anybody know?

Real1shepherd · May 23, 2021, 08:05:05 PM

Take whatever brand of non-ethanol farm store gas or premix product, go to their website and see the breakdown of ingredients. What I saw in there was not impressive for the price.

I think the canned premix products will run very clean in most all saws. I actually saw a vid of a saw before and after it had run about 4 tanks of the canned premix. All the carbon was excised out and things looked almost laboratory in there.

My problem is the price for what you get.

Kevin

nativewolf · May 23, 2021, 08:24:05 PM

Quote from: YellowHammer on May 23, 2021, 12:59:00 PM
Basically, what I'm saying is that aircraft engines have their fuel optimized specifically for them, and likewise, automotive engines have their fuels optimized for them. Boats utilize marine fuels specifically blended for them, also. As a practice, (people can do what they want) I put marine fuel in my boat, auto fuel in my car, and if I owned one, my airplane would get aviation fuel. Maybe I should also be feeding chainsaw fuel to my chainsaw, because it certainly seems to like it.

As with most things, the optimization of the fuel blend is a tradeoff based on its intended application. Thats why I'm interested to know what is in the premixed chainsaw fuel, I'd like to know what additives are involved, and if it has the effect of improving apparent performance while reducing engine life. Or maybe it will increase engine life. I don't know, thats why I ask.

Does anybody know?

I wish I knew too. What I do know is that 93 octane ethanol fuel has caused issues with our CM saws.
I've spent more money than I'd like to have spent on issues related to saws in the last year. None since we moved to premix. Why?