Inside the "Triple Nickel"

[Jim Timber]

I run a 16" on my 50-60cc saws. If I need more bar, I probably want more cubes too.

 

[sachsmo]

Some people just have to hate by nature. Must be a miserable life. Too bad he can't understand doing it just because it's something you enjoy. I've been doing build thread much longer than I've been a sponsor.

Careful there brad, I can hear your panties scrunching up from here.

I've been around and your benevolency has always been rewarded 10 fold.


You see I do it for the love of making something useless 'mobetter'.

You on the other hand do it for $$$$$$$$$$$$$$$$s.

Yep I can be a curmudgeon at times but when I need a good chuckle I just log on and poke you in the eye.


Sheeez you are so predictable!

 

[one.man.band]

Yes, that is also partly the idea too. R&D in Sweden watch the arborist forums all over the world, and porting is gaining in popularity, especially with the videos and images on how to do the improvements. The saw only needs to meet emissions laws until purchase.
In fact, I would go as far as saying brad probably helped the 201t improvements! After all, if the manufacturer can save a few million in R&D by watching what basic mods a porter has used


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i used to drink whiskey.......

 

[Mastermind]

Repped

 

[blsnelling]

Here's one of those EL48 carbs from EBay for $69. Now to get the module programmed.

 

[stihlaficionado]

Careful there brad, I can hear your panties scrunching up from here.

I've been around and your benevolency has always been rewarded 10 fold.


You see I do it for the love of making something useless 'mobetter'.

You on the other hand do it for $$$$$$$$$$$$$$$$s.

Yep I can be a curmudgeon at times but when I need a good chuckle I just log on and poke you in the eye.


Sheeez you are so predictable!

Everyone is predictable

 

[tlandrum]

Here's the 2260 ported. Don't advance the ignition on your 2260s or 562XPs. Also, I added a small notch in the butterfly directly inline with the transition passages. The hesitation remains. Looks like I'm going to have to pony up for a EL48.

ugh, well, ugh,,, is it faster than stock??

 

[blsnelling]

ugh, well, ugh,,, is it faster than stock??

You forgot to send me your programmer loaded with EL48 firmware

 

[LowVolt]

Electronic controlled carb for $69? Doesn't seem too bad....

 

[tlandrum]

after the day of carb swapping I had today,i lost faith in the el48. I ended up back with the el44 and el46 electronics to fix a saw.

 

[gunrush128]

Not what I wanted to hear... Did you happen to try the EL48 with the EL46 electronics?


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[tlandrum]

el48 and el46 have the same electronics. the el44 doesn't have the extra plug in for quick diagnostics

 

[gunrush128]

I was under the impression that the firmware was different between the two.
I wonder if the different throttle plate makes a difference between the 46 and 48? I guess I could do some experimenting on my own. There are also other visible differences between the two carbs.



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[tlandrum]

firm ware is different but the components are the same.

 

[boxygen]

Here's one of those EL48 carbs from EBay for $69. Now to get the module programmed.

Hutzl is getting pretty good huh?

 

[woods works]

This service bulletin makes everything perfectly clear.....................................................like mud

 

[Chris-PA]

Yet the 241m, 441 and 661 I've seen all had walbro.

If you want to disagree fine, but why is autotune patented but m-tronic only trade-marked?

Also, you can check various patent listings, I did before posting the reply. So I believe this time, you're full of it!

20140209078 <- autotune that's currently used
20140183315 <- magnet and sensor for the adjustment whilst running
20130332049 <- Rev-limiting autotune
20130133618 <- autotune memory/stats
20120318143 <- the current x-torq
20120304966 <- ignition timing control
20100011597 <- more autotune stuff!
20090145399 <- an autotune patent (this is what Stihl use)
20080302345 <- older form of the new x-torq

Oddly, Stihl own the patent for the x-torq that the 372xp uses:
20100242904
But this patent only happened in 2010, so I assume it must have been sold and transferred into Stihl's name


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Thanks for this information, there is a lot in here and I have not read them all yet. There is some basic stuff that may impact on the 562 problem, relative to strato engines in particular. With strato engines there are two paths for air to enter the engine, one which carries not fuel at WOT (the strato ports), and the traditional path that carries a reduced airflow into the crankcase which carries all the fuel at WOT. However, the fuel and air flow are configured differently at idle vs. WOT. There are two approaches used:

First, the original one used on the Zenoah GZ4000 and many others, with two separate throttle plates. Here the main air flow path is through the strato air valve (just air, not fuel), and a much smaller carb is used which must pass all the fuel at a reduced air flow into the case. This allows effectively reduced transfer duration at idle when the strato air valve is closed. This seems to work fine on my GZ4000's and clones, and many other stratos from what I understand.

However, I can see some potential pitfalls. With a large displacement engine with low case volume and good pumping efficiency, what happens at idle? The strato air valve is closed, and all the air flows through the carb with a venturi that is much smaller than a traditional carb for a non-strato saw of equivalent displacement. That mean it has a greater air velocity at idle, and a greater pressure drop at the fuel outlet port.

This may be an issue with the 562 given how tweaked it is with crank stuffers, etc. They have clearly been drilling holes in the throttle plate, possibly to allow air to flow through without picking up fuel. This can work, but it also raises idle speed. I have had a saw that simply pulled too much air at idle for the size carb that was on it, and it activated the main (H)
circuit a little at idle. The only way it would idle was with the L almost closed. I put a bigger carb on it and that cured it. This is why I wondered how the 562 AT system controls idle speed - if the holes in the throttle plate raise the idle, then the system will try to drop it down. IF it does that by retarding the timing, then at the moment you crack the throttle it will be sitting there with major retarded spark timing. But I have not found out if this is the method for idle speed control used.

The Second, newer approach uses a carb with a single throttle plate, and some vanes placed so that the throttle and choke plates separate the flow through the carb into air-only and fuel/air paths at WOT, the first feeding the strato ports and the second going to the case (normal carbs pretty much do this too, but both paths are joined at the outlet anyway). However, at idle the two paths are joined so there is no strato effect, but more importantly the idle fuel is intentionally introduced into the air path of the carb, and the effective venturi area is much bigger than the original strato small carb approach. That means the idle air velocity through the carb is lower and the pressure drop smaller - it's a bigger carb.

With this approach you cannot have different port timing for idle and WOT.

 

[Mastermind]

From what I've seen you are on the right track.

Just adding to what you posted......

"They have clearly been drilling holes in the throttle plate".....

And notches. The extra air that has been introduced must raise idle speed.......there ain't no way around that. To compensate, I believe that the AT system adds more fuel. That added fuel pools behind the throttle plate. Crack the throttle.......that fuel dumps into the case and causes a bog.

They can add all the bandaids they want.......but this issue is common, and tough to fix.

 

[Termite]

From what I've seen you are on the right track.

Just adding to what you posted......

"They have clearly been drilling holes in the throttle plate".....

And notches. The extra air that has been introduced must raise idle speed.......there ain't no way around that. To compensate, I believe that the AT system adds more fuel. That added fuel pools behind the throttle plate. Crack the throttle.......that fuel dumps into the case and causes a bog.

They can add all the bandaids they want.......but this issue is common, and tough to fix.

So you are saying it is a bog from being too rich,at the moment the throttle is opened. Which explains why when my saw is not fully up to temperature, (a little cool), there is no bog.

 

[Mastermind]

Si.