Carb Guru? WJ-69 and Clone comparison

[jmssaws]

Loading up/changing tune at idle, and insensitive H side needle are symptoms of leaking needle, low pop-off pressure or too soft of metering spring.

All 3 of mine act just like one with bad needles,very sensitive to adjustment.
If it's lean at a idle I can barely turn the low and it fat.

 

[srcarr52]

All 3 of mine act just like one with bad needles,very sensitive to adjustment.
If it's lean at a idle I can barely turn the low and it fat.

Did you check the pop-off pressure? Will it at least hold pressure?

I've seen burr's left on the seat, arms that are slightly tweaked, all sorts of things that cause the metering needle to not seal or seal sporadically. That is why I pressure test every carb with the diaphragm off, so I can bump the lever and make sure it reseats nicely. Then I test again with the diaphragm to make sure it's not holding the needle open.

 

[Chainsaw Jim]

Some of the kits that come installed in the clone carbs resemble gumball machine jewelry. Metering levers that bind with the pins and do not work smooth together. Or just the wrong metering lever shape in general.

 

[jmssaws]

I have put a oem kit in them and it changed nothing,needle and seat and arm are working fine. I think it's a problem with the h&l needles but I don't have anything to replace them with,oem is different.

I would really like to get them right because they make more power than oem.

 

[srcarr52]

I have put a oem kit in them and it changed nothing,needle and seat and arm are working fine. I think it's a problem with the h&l needles but I don't have anything to replace them with,oem is different.

I would really like to get them right because they make more power than oem.

Chuck the needle in the lathe or a drill and use a file to lessen the tapper. That will give you finer adjustment.

 

[jmssaws]

Chuck the needle in the lathe or a drill and use a file to lessen the tapper. That will give you finer adjustment.

Right on

 

[Chainsaw Jim]

Or maybe screw the needle in just tight enough to slightly reform the edge of the hole to better match the needle.

 

[srcarr52]

Or maybe screw the needle in extra tight to slightly reform the edge of the hole to better match the needle.

I was going to mention that as well but figured people would freak out about it. Chances are the machining of the needle and seat are not the best and they probably don't line up very well so you are getting more of an ellipse of fuel than the full circle.

 

[Chainsaw Jim]

I was going to mention that as well but figured people would freak out about it. Chances are the machining of the needle and seat are not the best and they probably don't line up very well so you are getting more of an ellipse of fuel than the full circle.

I would actually think it would be a good thing with a brand new carb to carefully tighten the screw down tight enough to "seat it" so to speak. Which they might actually do in the real walbro factory finish line.

 

[srcarr52]

I would actually think it would be a good thing with a brand new carb to carefully tighten the screw down tight enough to "seat it" so to speak. Which they might actually do in the real walbro factory finish line.

Probably, but I would think there is a fine line between seat and snap. I think the original Stihl needles actually bottom out on the stepped part so if you screw them in too hard it peens the orifice over and probably makes it smaller. But here we have a junk carb to begin with, might as well try.

 

[Cut4fun]

I tried an aftermarket carb on my 064 and it had excellent throttle response but had the crazy idle issue on the l side . I found 2 oem wj69s and rebuilt them and presto ! Listen to that tune

I have maybe 3-4 69's I have stolen parts from over time. Would have to check to make sure all 69's.

If I do have them they are a tradeable item.

 

[jmssaws]

I spent a couple hours this evening trying to get one right,the only way to keep it idling for more than 5 seconds is to leave it at 3k which is no good but Holy *s-word does it run good at wfo, I recorded the entire tuning process and a couple cuts but I somehow deleted all the tuning. Lol
I'll do it again in the morning,here's the cut part of it,no carb makes as much power that I've tried on this saw.

 

[Chainsaw Jim]

I apologize in advance if this was already covered, but I can't find where this was mentioned... did you say the main nozzle check valves held vacuum in these carbs after several repeated tests at one sitting?

 

[jmssaws]

I apologize in advance if this was already covered, but I can't find where this was mentioned... did you say the main nozzle check valves held vacuum in these carbs after several repeated tests at one sitting?

Never checked them.
You can't keep it idling at less than 3k
It's lean and the tiniest turn and I mean basically not move the low and it's immediately fat and if you don't lean the low a fraction it will kill it and you can repeat it over and over.
All 3 have been rebuilt,all 3 have been on multiple saws and all three are exactly the same.
Won't idle right but run like a mfr,what am I missing guys? I've tried everything but rework the needles and they act just like a old wore out carb that the shafts are leaking on and the needles are shot.

 

[Keith Gandy]

Never checked them.
You can't keep it idling at less than 3k
It's lean and the tiniest turn and I mean basically not move the low and it's immediately fat and if you don't lean the low a fraction it will kill it and you can repeat it over and over.
All 3 have been rebuilt,all 3 have been on multiple saws and all three are exactly the same.
Won't idle right but run like a mfr,what am I missing guys? I've tried everything but rework the needles and they act just like a old wore out carb that the shafts are leaking on and the needles are shot.

Tried the oem spring under the needle?

 

[huskihl]

J
How far out is the L when it does this?

 

[jmssaws]

Tried the oem spring under the needle?

All 3 have oem kits in them although I've used a 1000 am kits without trouble.

 

[jmssaws]

J
How far out is the L when it does this?

Always right at 1 and 1
If the saw is running it's doing it,I can tune on it for a hour and not move either more than just a tiny bit.
A few thousands of a turn makes drastic changes.

 

[Keith Gandy]

I wonder if notching the butterfly would help?

 

[huskihl]

I wonder if notching the butterfly would help?

Or if the butterfly is oriented like oem- notch on top or bottom