Summer heat and the 346XP

[SkwerI]

Willard, my comment was based on the assumption that the saw in question was running too lean, causing it to have issues with the heat. If somebody tells me that a saw acts up after running a while due to heat, then my first guess is that it's too lean and my second guess is that they are running it with a dull chain.

 

[NeTree]

I concur. I'll add that I've never heard of a "rich" seizure, but I suppose anything's possible.

 

[woodworkingboy]

I didn't mean to give the impression that anyone here was running their chains too tight, was referring to my neighbor. His practices can apply to a lot of chainsaw problem topics, really. He moved in with his wife, a retired couple, and since the place they bought has a wood stove, bought a chainsaw. A nice guy, I took pity. No previous experience at it, he drops by when there is a problem....kind of sudden like. A tough student, though, or it could be the teacher. I don't recall ever telling him that when the saw gets dull, you have to sharpen the rakers.

 

[Al Smith]

I concur. I'll add that I've never heard of a "rich" seizure, but I suppose anything's possible.

That's one of the reasons I run 32 to 1 but enough said about that .

I could have said I never hung one if a situation hadn't occured recently .I think I grabbed a squeeze bottle of straight gas and ruined a cylinder on a Mac .My fault from not paying attention ,head up azz . Things happen,the donor engine should arrive this afternoon by UPS .

 

[woodworkingboy]

I know of two cases where saws seized up due to the two cycle oil being put in but not shaken up. Fortunately, neither saw belonged to me.

 

[HolmenTree]

I concur. I'll add that I've never heard of a "rich" seizure, but I suppose anything's possible.

Damage can be done from an overich condition where the engine overheats from too much fuel mix. Varnish and gum builds up on the sides and top of piston, also in and around the ring area causing ring sticking.

 

[Magnus]

I think this has more to do with the quality and amount of oil needed when it is used rather than the amount of fuel in the air/fuel mix.
You can have them very fat and still not get carbon buildup, stuck rings etc if you know what and how to mix...

But scoring from excessive heat/overload when a saw running just by providing more fuel in correct mix for the saws setting I really doubt.
I don't think it can be done unless oil is the factor causing this.
Heat is needed to make oil turn in to carbon. If it run cold you get a substance that is mainly oil and sticky.

 

[Al Smith]

Along the same lines and first admitting I'm not an aviator .However I know several pilots and this is what they said on carbeurated air craft such as a small Cesana .

Once they made the climb to say 5-7000 feet or whatever they flew at ,they watched the cylinder head temperature and could lean out the carb for max fuel savings by keeping it at some predetermed temp .I'm thinkin 700 degrees ,could be wrong on that .Never the less depending on altitude,temperature etc .if it ran hotter than that they had to enriched the carb settings . BTW those old birds had the needle adjustment within the flight cabinet .If they do now of days I have not one clue .

 

[NeTree]

Correct, Al; as you climb, you must lean the mixture- because the air is less dense the higher you go, and this has the effect of making the mixture too rich. This is bad for fuel economy, and can foul the plugs. We can't just pull over if the motor fouls out. You can aim for 700 degrees CHT (or whatever temp is specified in the POH), but many small planes don't have this gauge, so you go by the tachometer- leaning for max rpm, then 1/2 to 3/4 turn richer.

Enriching the mix a little will cool a slightly overheated engine; for example, after flying a bit near stall (slow flight).

And yes, every plane with a carburetor and a gas piston engine still has a mixture control in the cockpit. It has a red knob, so you don't confuse it with the propeller pitch control, which is blue. They can be pushed and pulled, or turned for a fine control, and when pulled all the way out cut the fuel off completely.

 

[HolmenTree]

On the higher elevations on the PNW some of the saw competitions I used to go to were well above sea level , and I remember having to have to lean my saw's carb to get that "sweet spot" at WOT. Then the next competition at sea level I had to richen her up.

 

[pigwot]

First time across the continental divide in my old Volvo 122 had to stop and lean out the carb setting, and after the downhill, richen it up again.
I guess the control module and input from the mass air meter handles that these days...

 

[NeTree]

That would be why.

 

[CurSedVoyce]

I work between 1000 and 5000 foot levels normally.. You are always fine tuning a saw. Then add weather to the equation, high or low pressure.

 

[HolmenTree]

Pigwot, going back to your 346 thats giving you problems. I got a 346 with only about 40 tanks through it. Thing has been sitting on the shop floor since last fall. Its got that boggy lean condition between idle and WOT. Just haven't had time to tear it apart to find the leak or whatever. A mass of fuel, primer bulb and vent lines to work around with.
I sure miss the little guy but the 372 is about all I need for a ground saw now.
Still waiting to try out that "new" 560 / 562XP when ever they come out.

 

[Magnus]

I tried 560. Not much different from a 357. Not a felling saw like the 372.

 

[HolmenTree]

I tried 560. Not much different from a 357. Not a felling saw like the 372.

Thats what I heard too.Alot like a 357. The 560 should be a good running saw with its autotune technology.
I have a couple of 576XP AutoTunes that I only keep for my once a year chainsaw races in Feb. and their a very nice smooth running saw and cut like a 80cc

 

[Magnus]

I would like to try it out with same bars and chains we run on the 357 here, I tested it wit 13" bar almost got my a$$ handed to me as I suggested we try it with 16-18"...

 

[Magnus]

Edit... Oops... Wrong video

 

[Magnus]

Here it is:

 

[Magnus]

Out of the 372's I had here there is perhaps one out of these 50 or so that won't outcut any of the 575/576 I had here. Not a model that impress me.

The 560 seemed to get lots of heat the cuts I made in small soft wood... With 13"... Would be very interesting to get a tad longer bar and run it in some hardwood instead.
I get a feeling it would not act the same.

Auto tune is a step in right direction, but without any form of reference measurement in the system along with fuel system and a temp indicator or exhaust reader, it will be as good as the light they had on Jonsered 2051.
Two separate systems fighting each other is not very good, better is to have one that link the systems and knows what come out, not just rpm's.

 

[pigwot]

Willard,
If you find anything interesting with your 346xp I'd appreciate the heads up.
I brought mine with me (in Toledo, Ohio this evening, and Michigan for the next two weeks) to do some work at my parents' place.
Of course it's a bit cooler up north here...

 

[HolmenTree]

Patrick if I find something I'll let you know. I did a major carb service, fuel filter change , but still no help. I'm thinking primer bulb leak around the mess of lines it has.

Magnus thanks for the 560 video. With a 14-16"b/c that little saw will easily replace my 346, very snappy powerband for a 60cc and looks lightweight. I thought that the 576XP AutoTunes I have pulled a 32" better then my 372, good torque that's why I feel they cut like a 80cc.
I wonder how that new Stihl 441 with their auto tune is doing? Sounds a little more advanced then Huskies.

 

[Magnus]

You ever run a 262?
That was faster and more power than 560 from what I can tell.
Both limbing saws, both comparable to 357 that is to be replaced with 560/562.
It cuts better than the 346, but so do 359/357/262/257 etc...

You must have had a basket case 372 or something wrong...

 

[HolmenTree]

262XP first Husqvarna with air injection around 1990. When I worked for Stihl in 1989 we played with a 262xp, big development for saws at the time.
A 346XP NE is what it is ..a 50cc saw, probably one of the best power/weight saws out there. My 372 has a non rev limit module, mild muffler mod, carb screw limiters clipped...... she motors. From right out of the box the 576 AT s pulled a 32" bar through frozen 30"+ spruce impressively, better then my 372 when it first came out of the box.

From your video, were you reving the snot out of the 560 to get oil on the chain or checking the "rev boost"? You should have demoed that 560 in a piece of aspen , would be more impressive then that tough birch.

 

[Cut4fun]

You ever run a 262?
That was faster and more power than 560 from what I can tell.
Both limbing saws, both comparable to 357 that is to be replaced with 560/562.
It cuts better than the 346, but so do 359/357/262/257 etc...

.

I have never been impressed in the 262xp stock or muffler modded. Way over rated power wise. Only one that impressed me was on alky/nitro to date.