Mastermind
Work Saw Specialist
I'm just trying to keep up.
I've made a living standing on the shoulders of great men like you Mitch.
I've made a living standing on the shoulders of great men like you Mitch.
Mastermind And The 562XP
- Thread starter Mastermind
- Start date
Help Support Arborist Forum:
spike60
Addicted to ArboristSite
Started taking stuff apart here. First thing I wanted to look at is if my newer saws have the brass one or the new one and they have the brass one in there. May or may not be a big deal since this apparently doesn't affect all saws. Or at least doesn't affect them all to the same degree. Matt's was almost unusable. Some may have a slight bog that guys are living with.
mweba
Addicted to ArboristSite
Yeah it seems to be all over the spectrum. Most have no issue at all but the worse of them have been ported. Probably pushing the carb a bit more. This is why I recommended the EL44 with the current computer as they seem to have no issues. Fixing the 46 was the next step but I got busy with life and stuff.
Anyway, I've not started a thread on it as I wasn't ready to call it a 100% fix.
mweba
Addicted to ArboristSite
That and I didn't want to excite a crowd....which happened anyway.
Most of us don't understand carbs at that level to carry on an intelligent conversation about them.
That tube where the air mixes with the fuel as it gets sucked down into the engine, right?
I appreciate it when you figure things out and share them with us in simple terms, like you did in that butterfly video.
Philbert
Mastermind
Work Saw Specialist
One of my favorite films.
Terry Syd
Addicted to ArboristSite
Thanks for the pictures of the metering side of the carb. I compared them to the conventional C1M carb I had. I had to pull out the welch plugs to figure out where the circuits went.
There are considerable differences in the conventional and AT carbs.
As far as the hole in the nozzle, that would only affect the main circuit. The hole adds fuel to the nozzle by bypassing the conventional high speed screw or AT function. I don't think that is the problem. If you had an AT that couldn't keep up with the flow of a modded saw, then a drilled nozzle would be a fix.
The problem is the 'off idle' bog - something that is related to the ramp up on the low speed jet. Now here is where it gets weird. The conventional carb has a brass low speed jet, the AT carb doesn't appear to have the jet. Maybe it does and I just can't see it in the pictures. I'll take a picture of my conventional C1M so you can see what I'm on about (take a few minutes...)
I can't see where the AT carb is getting the fuel for the idle/transition circuits in the pictures. If we can locate where those circuits are receiving their fuel, then we may get closer to figuring out this problem.
There are considerable differences in the conventional and AT carbs.
As far as the hole in the nozzle, that would only affect the main circuit. The hole adds fuel to the nozzle by bypassing the conventional high speed screw or AT function. I don't think that is the problem. If you had an AT that couldn't keep up with the flow of a modded saw, then a drilled nozzle would be a fix.
The problem is the 'off idle' bog - something that is related to the ramp up on the low speed jet. Now here is where it gets weird. The conventional carb has a brass low speed jet, the AT carb doesn't appear to have the jet. Maybe it does and I just can't see it in the pictures. I'll take a picture of my conventional C1M so you can see what I'm on about (take a few minutes...)
I can't see where the AT carb is getting the fuel for the idle/transition circuits in the pictures. If we can locate where those circuits are receiving their fuel, then we may get closer to figuring out this problem.
Terry Syd
Addicted to ArboristSite
Now you can see the brass low speed jet. The jet sits directly under the two transition holes in the throttle bore. There is actually a hidden passage from the low speed jet to the long trough that leads to the idle hole. With the welch plug pulled off I could see where the fuel came up out of the 'well' in the center of the carb and fed back to the idle hole.
On the conventional carb the low speed needle controls the fuel coming up out of the 'well'.
The other circuit on the other side of the brass jet is the high speed circuit. It gets it fuel from the large hole next to the brass jet and then jumps up over the low speed circuit to drop down into the small hole close to the nozzle. The high speed needle then controls the fuel going to the nozzle.
On the conventional carb the low speed needle controls the fuel coming up out of the 'well'.
The other circuit on the other side of the brass jet is the high speed circuit. It gets it fuel from the large hole next to the brass jet and then jumps up over the low speed circuit to drop down into the small hole close to the nozzle. The high speed needle then controls the fuel going to the nozzle.
Terry Syd
Addicted to ArboristSite
OK, if the drilled nozzle fixes a bogging problem, then what it is doing is bypassing the AT software.
It may be that the AT is recalibrating at extended idle and when the throttle is cracked WOT it can't keep up with the new demand, it just can't move fast enough. So, they drilled the nozzle to get some flow through it and the AT can then fine tune the flow.
It may be that the AT is recalibrating at extended idle and when the throttle is cracked WOT it can't keep up with the new demand, it just can't move fast enough. So, they drilled the nozzle to get some flow through it and the AT can then fine tune the flow.
stihlonlynow
ArboristSite Operative
[quTerry Syd, post: 4667411, member: 32073"]OK, if the drilled nozzle fixes a bogging problem, then what it is doing is bypassing the AT software.
It may be that the AT is recalibrating at extended idle and when the throttle is cracked WOT it can't keep up with the new demand, it just can't move fast enough. So, they drilled the nozzle to get some flow through it and the AT can then fine tune the flow.[/quote]
It didnt fix the bog on mine. The hesitation gets worse after an idle of 15 seconds. The longer its left at idle the greater the hesitation.
It may be that the AT is recalibrating at extended idle and when the throttle is cracked WOT it can't keep up with the new demand, it just can't move fast enough. So, they drilled the nozzle to get some flow through it and the AT can then fine tune the flow.[/quote]
It didnt fix the bog on mine. The hesitation gets worse after an idle of 15 seconds. The longer its left at idle the greater the hesitation.
stihlonlynow
ArboristSite Operative
If you only let it idle for a couple of seconds it doesnt hesitate much if at all.
Any chance that they're actually loading up at idle, then stumbling when it sucks that excess fuel in when you go WOT? My experience with Stihl stratos is that they need to be tuned very lean at idle for good throttle response.
Terry Syd
Addicted to ArboristSite
There's a good way to test that theory, simply increase the POP. Take a beer can and cut a small disk to put in the metering spring well. The metering spring will sit higher and create more POP. If it doesn't work, just remove the disk.
Here's something that nobody has mentioned - what kind of tank vent does this thing have?
As I mentioned before, I have 'lost' all my EPA vents. I don't know where they disappeared to, so I had to make up fully vented tanks.
Here's something that nobody has mentioned - what kind of tank vent does this thing have?
As I mentioned before, I have 'lost' all my EPA vents. I don't know where they disappeared to, so I had to make up fully vented tanks.
Swapping the nozzle on the el46 had no effect for me today. Altering popoff did nothing either. Maybe g this is just one really bad 46 but this saw is getting the 44 put back on it so it's owner can go murder some wood.
I'll play with this carb more later on my own personal time. Don't think the customer is going to be happy when he gets the bill for all the labor I have into this saw.... Gotta be at least 4-6 hours, a carb, parts, etc..... Sorry homie.
Sent from my SM-T210R using Tapatalk
I'll play with this carb more later on my own personal time. Don't think the customer is going to be happy when he gets the bill for all the labor I have into this saw.... Gotta be at least 4-6 hours, a carb, parts, etc..... Sorry homie.
Sent from my SM-T210R using Tapatalk
Terry Syd
Addicted to ArboristSite
When I first started playing around with these various carbs I found more than a few things that could give the carb a different designation. The carb body could have a smaller or larger metering orifice (that affects the POP and the length of the 'ramp' for the low speed jet). Another one is the size of the low speed jet. Two things that are easy to miss when looking at carbs.
I understand how a conventional C1M gets fuel to the low speed circuit and how that fuel flow is controlled, but I ain't got no idea about the AT C1M. A close up picture of the metering chamber might give me a clue.
If someone has one of these carbs that is 'excess', they might want to pull the welch plugs and see how it is configured.
If this turns out to be a tank vent problem, Husky is going to have some explaining to do...
EDIT: If someone can get a hold of one of the green vented tank caps, they may be able to test the tank vent theory.
I understand how a conventional C1M gets fuel to the low speed circuit and how that fuel flow is controlled, but I ain't got no idea about the AT C1M. A close up picture of the metering chamber might give me a clue.
If someone has one of these carbs that is 'excess', they might want to pull the welch plugs and see how it is configured.
If this turns out to be a tank vent problem, Husky is going to have some explaining to do...
EDIT: If someone can get a hold of one of the green vented tank caps, they may be able to test the tank vent theory.
Last edited:
