Mastermind
Work Saw Specialist
I like that idea.
Inside the "Triple Nickel"
- Thread starter blsnelling
- Start date
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If you hook up to a new saw and set the TPS at 100% within 5 hours the TPS is usually below 94%. Resetting it again and running it the variation is lesser, but it is there. If you look at the saws with the negative transition, be it the 550,555 or 562 the TPS values are low. Initial cable stretch? Don't know, theres not enough data, but doing an update which should, on the part of the person doing an update include function tests, clears things up in most cases.
The joys of the AT games, a lot of little variable have a profound effect.
I have a shop 562, a customers that I finally said enough is enough out of warranty and gave him a new unit with an EL46 that's working like a charm. His previous 562, with the EL44, well lets get started, crankcase gasket, muffler, av springs, clutch, carb, crank bearing. Pretty much everything that could fail did before 59 hours, which is a lot of run time in reality. Its all back together and I will be going to cut wood with it tomorrow, along with its newer EL46 carb, runs like a champ.
The EL44 became the EL46 for no tech wanted to wrestle with the 44' s service hook up. Initial 46's are no different that the 44's, just that there are a lot more 46's out in users hands.
The joys of the AT games, a lot of little variable have a profound effect.
I have a shop 562, a customers that I finally said enough is enough out of warranty and gave him a new unit with an EL46 that's working like a charm. His previous 562, with the EL44, well lets get started, crankcase gasket, muffler, av springs, clutch, carb, crank bearing. Pretty much everything that could fail did before 59 hours, which is a lot of run time in reality. Its all back together and I will be going to cut wood with it tomorrow, along with its newer EL46 carb, runs like a champ.
The EL44 became the EL46 for no tech wanted to wrestle with the 44' s service hook up. Initial 46's are no different that the 44's, just that there are a lot more 46's out in users hands.
Chris-PA
Where the Wild Things Are
Yes, those notches can be used to direct flow toward or away from fuel outlet ports. However, given how many there are and where they are located it would appear they are intended to direct flow away from fuel ports, and therefore to prevent picking up more fuel.
Awful shame you didn't pick up on it almost a year ago, when I first brought it up.
When we want to find the know it all about AT were gonna have to go on a road trip to Europe, then spend some time in China, then just for the hell of it a week in Dublin!
Mastermind
Work Saw Specialist
I must have had you on ignore. 
To each there own.
You can do your usual when I post something on the 562 threads, I don't mind, my ignore button is a cord in the wall.
You can do your usual when I post something on the 562 threads, I don't mind, my ignore button is a cord in the wall.
Mastermind
Work Saw Specialist
I've enjoyed this conversation Hamish.
I appreciate your help.
I appreciate your help.
So the idle bog, or negative transition, is related to throttle position sensor cable tension or slack? Is there a threshold in there somewhere where the problem appears or disappears?
Mastermind
Work Saw Specialist
I've been able to fix it by replacing the 46 with a 44. I use the 46 module on the 44.
Right. That's where I'm confused. If Hamish is right that the 46 and 44 are essentially the same carburetor, then he has noticed a connection between the TPS percentage number and the appearance of the bog. That is interesting if it holds up under more testing or your experience with these things. It would make sense that a throttle position mismatch between the actual throttle position and where the sensor thinks it is could have a bad effect. So I thought I would ask for clarification on just what the TPS at 100% or 94% really means.
Mastermind
Work Saw Specialist
I noticed that the TSP bounced around a little too much when testing these carbs with the diagnostic setup. To get a cleaner reading between the magnets and the pickup, I shimmed the magnets (that are on the throttle shaft) out closer to the pickup sensor.
That helps these things a bunch.
That helps these things a bunch.
Do you think there are several things all going on at once? There was progress made by notching the throttle plates, and it seems there is progress being made by working with the TPS signal. I had meant to ask you about the fuel puddling idea as well, which may also be involved. I wanted to see if you would expand on it. Would the puddle go away if the saw was oriented properly, or drip out the carb throat where it could be seen if the saw was idled on its side. That seems like the type of idea you could test to see if it held up under scrutiny.
I bolted on my new EL48 tonight, using the module that was on the EL46. I knew it was a different saw as soon as I started it. There might be the slightest hint of a hesitation after it's hot, but you almost have to imagine it to notice it. It made a big difference. I'm going to send the module out to be programmed and see how that does. I'm feeling good about this 
And on that note, good night to all. For not having one of these saws, I've really enjoyed following the detective story of trying to get them to run right....I bolted on my new EL48 tonight, using the module that was on the EL46. I knew it was a different saw as soon as I started it. There might be the slightest hint of a hesitation after it's hot, but you almost have to imagine it to notice it. It made a big difference. I'm going to send the module out to be programmed and see how that does. I'm feeling good about this
At WOT the TPS should read 100% (aka full throttle). From an idle standpoint the butterfly would be at the idle position whereas the fuel valve as mapped is not.
Now that my little mind can comprehended. It makes sense.
I'm no fanboy of any one brand, but I sure like my Husqvarna's. With that said this issue should have been rectified within weeks, but unfortunately it seems to be an ongoing problem. Not good!
I still cringe every time I see made in China.
gaspipe
Expert Beer Drinker
I just wish to extend my sincerest thanks to the EPA for saving us from the plight of chainsaw pollution. Please carry on.
Maybe so. However if you want to stay in business you must work within the constraints, or go out of business. The blame falls on the manufacturer IMHO.
Chris-PA
Where the Wild Things Are
Now ask yourself why the US market is not flooded with Chinese saws like in OZ?
That's interesting - but nothing says the software cannot interpret a reading of 94% as full throttle. It's not a big deal to compensate for hardware tolerance in software this way, in fact it's pretty common. TPS in cars are pretty sloppy too, but the system corrects for that.
Anyway, just pointing out that the diagnostics might just be giving a raw value from the sensor, it may not indicate a problem. However, if it makes it work better that's a more significant indicator. If it doesn't see the throttle move it won't respond. That would be kinda pathetic if it's what's wrong.
one.man.band
ArboristSite Guru
prevent? ... when air velocity increases.... quicker transition over to main ...helps pick up fuel from main sooner
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