The chainsaw thread...

[DougW]

Has this ever happened to anybody? Was bucking firewood at a slash pile pretty hot day 27C or so and cutting pretty continuously for 5 hours . Had a hard time restarting which I usually don't have. I checked fuel and of course the tank was pressurized from the heat but after I opened the gas in the tank kept on bubbling for quite a while , 30 seconds or so . So was that the reason I couldn't restart ? vapour lock?

[bodywhomper]

Hasnt happened to me. Do u think that gas was "flowing" into the cylinder and flooding your engine?

Sent from my SPH-L710 using TGR Forums mobile app

[XXX-er]

no but I'm usually more concerned with trying to stay warm

[mooseknuckle]

I think on a 50cc engine, for the most part, you are going to be underpowered if you are cutting with most of the bar. And if you don't have the power to efficiently use the whole bar length, why even have it on?

Concur. Listen - it’ll get through it with a 20” bar, but my 261 is not exactly a power house. I subscribed to the theory at the time that you buy the smallest pro saw (excluding climbing saws of course). Now I’m going to make a change and size up on powerhead.

The 462 is ridiculous. Heavier for sure, but the weight to power ratio is unreal. #stihlprosawfanboi

[DougW]

Hasnt happened to me. Do u think that gas was "flowing" into the cylinder and flooding your engine?

Sent from my SPH-L710 using TGR Forums mobile app

Don't know. Maybe it was so hot that gas was boiling with release of pressure. It was already not starting so I don't think that me putting on side and opening up tank had any effect. There is one thing I can do for summer operation is switch the fitting on the spark plug 180 deg , the shutter?. Not sure what that does but if I go out in that kind of heat will try.

the reverse of the following as my saw came in winter op mode as far as the shutter is concerned

The first thing to do to prepare your chainsaw for use in temperatures under 40° F is to switch the winter/summer shutter on your saw to “winter” to activate the carburetor pre-heater system, if your chainsaw has this feature. Leaving the shutter on the summer position could result in carburetor icing, causing the machine to perform poorly, idle erratically, and even run lean, which could eventually cause major engine failure.

[bodywhomper]

Idk. I often run my saws above 27*C, and almost always run them in “summer” mode with the shutter position. I’ve never noticed my fuel bubbling like you described. Mine typical “won’t start” problem is because of accidental engine flooding. But see neofox’s conversation piece up thread where several people were thinking the problem was with the ignition coil. My first saw (not in use) had ignition coil problems, too, which behaved similar to your description without the bubble fuel.

[DougW]

To see the bubbles one would have to open up the fuel tank knowing that it was mostly full. I can't remember why I did that.

will do the changeover of the shutter if operating in hot weather know that I know or maybe just not buck for 4 hours in the hot sun, wait for a cooler day or wait till fall. It did get me to change my spark plug after 16 years of use.

[claymond]

To see the bubbles one would have to open up the fuel tank knowing that it was mostly full. I can't remember why I did that.

will do the changeover of the shutter if operating in hot weather know that I know or maybe just not buck for 4 hours in the hot sun, wait for a cooler day or wait till fall. It did get me to change my spark plug after 16 years of use.

Try changing the tank vent.

Did it over rev prior to shutting it off?

Saw I've used for the past couple summers will do that if we don't change out the tank vent often. One of it's quirks

[BCMtnHound]

Have you blown out or otherwise cleaned out your engine cooling fins? Back in antiquity when I ran saw for money, that was a weekly requirement on the 44 to keep her cool in the summer.

[XXX-er]

clean out fins, swap/wash air filter for the one drying on my Rancillio Sylvia, clean out bar slot & sharpen both chains with the jig apres every day of running

the clean bar & super sharp chain makes the most difference in being able to run a 20" bar IMO

[char_]

Tank over pressure is a documented thing in wildland fire that has resulted in a few people getting serious burns. I haven't read about a definitive reason it is occurring.

[neufox47]

Any of you running modified exhausts? Many seem to think it is the easiest way to increase power and it also is better for the engine. Seems crazy to modify a brand new saw though.

[DougW]

Any of you running modified exhausts? Many seem to think it is the easiest way to increase power and it also is better for the engine. Seems crazy to modify a brand new saw though.

oh no , as long as starts I'm good, I just replaced the original spark plug after 13 years so if that is an indication. So could be combo of spark plug and not changing over the shutter for hot day.

As per vent, I don't think my saw has that MS290, nothing in manual but manual does say to opening slowly/carefully so pressure releases slowly, which means to me tank is not vented.

Was cleaning filter and once took it off to clean back side.

[XXX-er]

I believe if you fuck with the muffler you gotta fuck with the jetting, change the engine back-pressure and it changes other things ... think of the saw as an air pump

In the 261 manual there is a "winter operation" page tells you how to change the shutter, I think you take it out and put it in the other way, I've never touched it

[bodywhomper]

I modded the muffler on my used ms361. There's a huge thread about it on arboristsite.com. i followed some pretty clean instructions because too big of a new hole can be bad. I also made sure i modded in a way that i could have a spark arrester on the new hole. I also had to change the settings on my carb. The change definitely improved engine performance and power. It uses fuel more quickly, too. At the time, i was overhauling the saw and it was pretty simple compared to everything else i was doing to it.

Sent from my SPH-L710 using TGR Forums mobile app

[DougW]

I believe if you fuck with the muffler you gotta fuck with the jetting, change the engine back-pressure and it changes other things ... think of the saw as an air pump

In the 261 manual there is a "winter operation" page tells you how to change the shutter, I think you take it out and put it in the other way, I've never touched it

Mine has always been in winter position and never thought of touching it till now, I've seen the symbols on the case for the two positions but until I looked at the manual couldn't see how to do it. It usually cool in morning and cutting a lot in hot conditions is something I try to avoid. But we set the date and was trying to fill trailer. The others guys saw MS271 I think was also having issues with the heat.

what does the shutter position do? The manual has winter operation was the odd case and this says what happens if you operate in summer position in winter
"The first thing to do to prepare your chainsaw for use in temperatures under 40° F is to switch the winter/summer shutter on your saw to “winter” to activate the carburetor pre-heater system, if your chainsaw has this feature. Leaving the shutter on the summer position could result in carburetor icing, causing the machine to perform poorly, idle erratically, and even run lean, which could eventually cause major engine failure." from Stihl site

But can't find anywhere what happens if in 'winter " in hot. If winter mode has preheat then by logic if in winter in hot weather then too much heat going into carburetor? causing ?

[claymond]

oh no , as long as starts I'm good, I just replaced the original spark plug after 13 years so if that is an indication. So could be combo of spark plug and not changing over the shutter for hot day.

As per vent, I don't think my saw has that MS290, nothing in manual but manual does say to opening slowly/carefully so pressure releases slowly, which means to me tank is not vented.

Was cleaning filter and once took it off to clean back side.

Yeah I'm not familiar with 290s, but I'm pretty sure it would still be vented. This is one on a 461 with air filter cover removed, the raised black circle part on top of the tank above the warning label.

[neufox47]

Yea, I decided I’m not fucking with it until the warranty is up. I saw where they said the chipped saws will adjust to getting less exhaust back pressure automatically.

[DougW]

Yeah I'm not familiar with 290s, but I'm pretty sure it would still be vented. This is one on a 461 with air filter cover removed, the raised black circle part on top of the tank above the warning label.

no don't have that but there is a line that goes to carb in about the same place which I don't think is the fuel line so probably a pressure equalization line

[bodywhomper]

The fuel tank vent on one of my stihl saws is on the clutch side of the saw. You should be able to get a pdf version of the tech manual of the saw online. It’ll eliminate the some of the guess work.

[Meadow Skipper]

https://www.instagram.com/forestproud/p/By_eOr2o3wj/

[sb]

[Meadow Skipper]

^So strange.

[mooseknuckle]

Selling huh? You in N Cal?

Unfortunately not. Central Pyay!

[neufox47]

Well got the ms-261 with 20” bar. I think I’m going to get a 16” bar and chain to go with it. Anyone know how small / narrow of a chain I can go? Looks like Stihl says .325 and .050